Provided by: gpg_2.4.7-17ubuntu3_amd64 
NAME
gpg - OpenPGP encryption and signing tool
SYNOPSIS
gpg [--homedir dir] [--options file] [options] command [args]
DESCRIPTION
gpg is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a tool to provide digital encryption and
signing services using the OpenPGP standard. gpg features complete key management and all the bells and
whistles you would expect from a full OpenPGP implementation.
There are two main versions of GnuPG: GnuPG 1.x and GnuPG 2.x. GnuPG 2.x supports modern encryption
algorithms and thus should be preferred over GnuPG 1.x. You only need to use GnuPG 1.x if your platform
doesn't support GnuPG 2.x, or you need support for some features that GnuPG 2.x has deprecated, e.g.,
decrypting data created with PGP-2 keys.
If you are looking for version 1 of GnuPG, you may find that version installed under the name gpg1.
RETURN VALUE
The program returns 0 if there are no severe errors, 1 if at least a signature was bad, and other error
codes for fatal errors.
Note that signature verification requires exact knowledge of what has been signed and by whom it has been
signed. Using only the return code is thus not an appropriate way to verify a signature by a script.
Either make proper use or the status codes or use the gpgv tool which has been designed to make signature
verification easy for scripts.
WARNINGS
Use a good password for your user account and make sure that all security issues are always fixed on your
machine. Also employ diligent physical protection to your machine. Consider to use a good passphrase as
a last resort protection to your secret key in the case your machine gets stolen. It is important that
your secret key is never leaked. Using an easy to carry around token or smartcard with the secret key is
often a advisable.
If you are going to verify detached signatures, make sure that the program knows about it; either give
both filenames on the command line or use ‘-’ to specify STDIN.
For scripted or other unattended use of gpg make sure to use the machine-parseable interface and not the
default interface which is intended for direct use by humans. The machine-parseable interface provides a
stable and well documented API independent of the locale or future changes of gpg. To enable this
interface use the options --with-colons and --status-fd. For certain operations the option --command-fd
may come handy too. See this man page and the file ‘DETAILS’ for the specification of the interface.
Note that the GnuPG ``info'' pages as well as the PDF version of the GnuPG manual features a chapter on
unattended use of GnuPG. As an alternative the library GPGME can be used as a high-level abstraction on
top of that interface.
INTEROPERABILITY
GnuPG tries to be a very flexible implementation of the OpenPGP standard. In particular, GnuPG implements
many of the optional parts of the standard, such as the SHA-512 hash, and the ZLIB and BZIP2 compression
algorithms. It is important to be aware that not all OpenPGP programs implement these optional algorithms
and that by forcing their use via the --cipher-algo, --digest-algo, --cert-digest-algo, or
--compress-algo options in GnuPG, it is possible to create a perfectly valid OpenPGP message, but one
that cannot be read by the intended recipient.
There are dozens of variations of OpenPGP programs available, and each supports a slightly different
subset of these optional algorithms. For example, until recently, no (unhacked) version of PGP supported
the BLOWFISH cipher algorithm. A message using BLOWFISH simply could not be read by a PGP user. By
default, GnuPG uses the standard OpenPGP preferences system that will always do the right thing and
create messages that are usable by all recipients, regardless of which OpenPGP program they use. Only
override this safe default if you really know what you are doing.
If you absolutely must override the safe default, or if the preferences on a given key are invalid for
some reason, you are far better off using the --pgp6, --pgp7, or --pgp8 options. These options are safe
as they do not force any particular algorithms in violation of OpenPGP, but rather reduce the available
algorithms to a "PGP-safe" list.
COMMANDS
Commands are not distinguished from options except for the fact that only one command is allowed.
Generally speaking, irrelevant options are silently ignored, and may not be checked for correctness.
gpg may be run with no commands. In this case it will print a warning perform a reasonable action
depending on the type of file it is given as input (an encrypted message is decrypted, a signature is
verified, a file containing keys is listed, etc.).
If you run into any problems, please add the option --verbose to the invocation to see more diagnostics.
Commands not specific to the function
--version
Print the program version and licensing information. Note that you cannot abbreviate this
command.
--help
-h Print a usage message summarizing the most useful command-line options. Note that you cannot
arbitrarily abbreviate this command (though you can use its short form -h).
--warranty
Print warranty information.
--dump-options
Print a list of all available options and commands. Note that you cannot abbreviate this command.
Commands to select the type of operation
--sign
-s Sign a message. This command may be combined with --encrypt (to sign and encrypt a message),
--symmetric (to sign and symmetrically encrypt a message), or both --encrypt and --symmetric (to
sign and encrypt a message that can be decrypted using a secret key or a passphrase). The signing
key is chosen by default or can be set explicitly using the --local-user and --default-key
options.
--clear-sign
--clearsign
Make a cleartext signature. The content in a cleartext signature is readable without any special
software. OpenPGP software is only needed to verify the signature. cleartext signatures may
modify end-of-line whitespace for platform independence and are not intended to be reversible.
The signing key is chosen by default or can be set explicitly using the --local-user and
--default-key options.
--detach-sign
-b Make a detached signature.
--encrypt
-e Encrypt data to one or more public keys. This command may be combined with --sign (to sign and
encrypt a message), --symmetric (to encrypt a message that can be decrypted using a secret key or
a passphrase), or --sign and --symmetric together (for a signed message that can be decrypted
using a secret key or a passphrase). --recipient and related options specify which public keys to
use for encryption.
--symmetric
-c Encrypt with a symmetric cipher using a passphrase. The default symmetric cipher used is AES-128,
but may be chosen with the --cipher-algo option. This command may be combined with --sign (for a
signed and symmetrically encrypted message), --encrypt (for a message that may be decrypted via a
secret key or a passphrase), or --sign and --encrypt together (for a signed message that may be
decrypted via a secret key or a passphrase). gpg caches the passphrase used for symmetric
encryption so that a decrypt operation may not require that the user needs to enter the
passphrase. The option --no-symkey-cache can be used to disable this feature.
--store
Store only (make a simple literal data packet).
--decrypt
-d Decrypt the file given on the command line (or STDIN if no file is specified) and write it to
STDOUT (or the file specified with --output). If the decrypted file is signed, the signature is
also verified. This command differs from the default operation, as it never writes to the filename
which is included in the file and it rejects files that don't begin with an encrypted message.
--verify
Assume that the first argument is a signed file and verify it without generating any output. With
no arguments, the signature packet is read from STDIN. If only one argument is given, the
specified file is expected to include a complete signature.
With more than one argument, the first argument should specify a file with a detached signature
and the remaining files should contain the signed data. To read the signed data from STDIN, use
‘-’ as the second filename. For security reasons, a detached signature will not read the signed
material from STDIN if not explicitly specified.
Note: If the option --batch is not used, gpg may assume that a single argument is a file with a
detached signature, and it will try to find a matching data file by stripping certain suffixes.
Using this historical feature to verify a detached signature is strongly discouraged; you should
always specify the data file explicitly.
Note: When verifying a cleartext signature, gpg verifies only what makes up the cleartext signed
data and not any extra data outside of the cleartext signature or the header lines directly
following the dash marker line. The option --output may be used to write out the actual signed
data, but there are other pitfalls with this format as well. It is suggested to avoid cleartext
signatures in favor of detached signatures.
Note: With option --batch he verification of signatures stops at the first bad signature. This is
a safe default for unattended processing but sometimes a status for all signatures is needed. To
override this early bailout use the option --proc-all-sigs.
Note: To check whether a file was signed by a certain key the option --assert-signer can be used.
As an alternative the gpgv tool can be used. gpgv is designed to compare signed data against a
list of trusted keys and returns with success only for a good signature. It has its own manual
page.
--multifile
This modifies certain other commands to accept multiple files for processing on the command line
or read from STDIN with each filename on a separate line. This allows for many files to be
processed at once. --multifile may currently be used along with --verify, --encrypt, and
--decrypt. Note that --multifile --verify may not be used with detached signatures.
--verify-files
Identical to --multifile --verify.
--encrypt-files
Identical to --multifile --encrypt.
--decrypt-files
Identical to --multifile --decrypt.
--list-keys
-k
--list-public-keys
List the specified keys. If no keys are specified, then all keys from the configured public
keyrings are listed.
Never use the output of this command in scripts or other programs. The output is intended only
for humans and its format is likely to change. The --with-colons option emits the output in a
stable, machine-parseable format, which is intended for use by scripts and other programs.
--list-secret-keys
-K List the specified secret keys. If no keys are specified, then all known secret keys are listed.
A # after the initial tags sec or ssb means that the secret key or subkey is currently not usable.
We also say that this key has been taken offline (for example, a primary key can be taken offline
by exporting the key using the command --export-secret-subkeys). A > after these tags indicate
that the key is stored on a smartcard. See also --list-keys.
--check-signatures
--check-sigs
Same as --list-keys, but the key signatures are verified and listed too. Note that for
performance reasons the revocation status of a signing key is not shown. This command has the
same effect as using --list-keys with --with-sig-check.
The status of the verification is indicated by a flag directly following the "sig" tag (and thus
before the flags described below. A "!" indicates that the signature has been successfully
verified, a "-" denotes a bad signature and a "%" is used if an error occurred while checking the
signature (e.g. a non supported algorithm). Signatures where the public key is not available are
not listed; to see their keyids the command --list-sigs can be used.
For each signature listed, there are several flags in between the signature status flag and keyid.
These flags give additional information about each key signature. From left to right, they are
the numbers 1-3 for certificate check level (see --ask-cert-level), "L" for a local or non-
exportable signature (see --lsign-key), "R" for a nonRevocable signature (see the --edit-key
command "nrsign"), "P" for a signature that contains a policy URL (see --cert-policy-url), "N" for
a signature that contains a notation (see --cert-notation), "X" for an eXpired signature (see
--ask-cert-expire), and the numbers 1-9 or "T" for 10 and above to indicate trust signature levels
(see the --edit-key command "tsign").
--locate-keys
--locate-external-keys
Locate the keys given as arguments. This command basically uses the same algorithm as used when
locating keys for encryption and may thus be used to see what keys gpg might use. In particular
external methods as defined by --auto-key-locate are used to locate a key if the arguments comain
valid mail addresses. Only public keys are listed.
The variant --locate-external-keys does not consider a locally existing key and can thus be used
to force the refresh of a key via the defined external methods. If a fingerprint is given and and
the methods defined by --auto-key-locate define LDAP servers, the key is fetched from these
resources; defined non-LDAP keyservers are skipped.
--show-keys
This commands takes OpenPGP keys as input and prints information about them in the same way the
command --list-keys does for locally stored key. In addition the list options show-unusable-uids,
show-unusable-subkeys, show-notations and show-policy-urls are also enabled. As usual for
automated processing, this command should be combined with the option --with-colons.
--fingerprint
List all keys (or the specified ones) along with their fingerprints. This is the same output as
--list-keys but with the additional output of a line with the fingerprint. May also be combined
with --check-signatures. If this command is given twice, the fingerprints of all secondary keys
are listed too. This command also forces pretty printing of fingerprints if the keyid format has
been set to "none".
--list-packets
List only the sequence of packets. This command is only useful for debugging. When used with
option --verbose the actual MPI values are dumped and not only their lengths. Note that the
output of this command may change with new releases.
--edit-card
--card-edit
Present a menu to work with a smartcard. The subcommand "help" provides an overview on available
commands. For a detailed description, please see the Card HOWTO at
https://gnupg.org/documentation/howtos.html#GnuPG-cardHOWTO . Please note that the command
"openpgp" can be used to switch to the OpenPGP application of cards which by default are
presenting another application (e.g. PIV).
--card-status
Show the content of the smart card.
--change-pin
Present a menu to allow changing the PIN of a smartcard. This functionality is also available as
the subcommand "passwd" with the --edit-card command.
--delete-keys name
Remove key from the public keyring. In batch mode either --yes is required or the key must be
specified by fingerprint. This is a safeguard against accidental deletion of multiple keys. If
the exclamation mark syntax is used with the fingerprint of a subkey only that subkey is deleted;
if the exclamation mark is used with the fingerprint of the primary key the entire public key is
deleted.
--delete-secret-keys name
Remove key from the secret keyring. In batch mode the key must be specified by fingerprint. The
option --yes can be used to advise gpg-agent not to request a confirmation. This extra pre-
caution is done because gpg can't be sure that the secret key (as controlled by gpg-agent) is only
used for the given OpenPGP public key. If the exclamation mark syntax is used with the
fingerprint of a subkey only the secret part of that subkey is deleted; if the exclamation mark is
used with the fingerprint of the primary key only the secret part of the primary key is deleted.
--delete-secret-and-public-key name
Same as --delete-key, but if a secret key exists, it will be removed first. In batch mode the key
must be specified by fingerprint. The option --yes can be used to advise gpg-agent not to request
a confirmation.
--export
Either export all keys from all keyrings (default keyring and those registered via option
--keyring), or if at least one name is given, those of the given name. The exported keys are
written to STDOUT or to the file given with option --output. Use together with --armor to mail
those keys.
--send-keys keyIDs
Similar to --export but sends the keys to a keyserver. Fingerprints may be used instead of key
IDs. Don't send your complete keyring to a keyserver --- select only those keys which are new or
changed by you. If no keyIDs are given, gpg does nothing.
Take care: Keyservers are by design write only systems and thus it is not possible to ever delete
keys once they have been send to a keyserver.
--export-secret-keys
--export-secret-subkeys
Same as --export, but exports the secret keys instead. The exported keys are written to STDOUT or
to the file given with option --output. This command is often used along with the option --armor
to allow for easy printing of the key for paper backup; however the external tool paperkey does a
better job of creating backups on paper. Note that exporting a secret key can be a security risk
if the exported keys are sent over an insecure channel.
The second form of the command has the special property to render the secret part of the primary
key useless; this is a GNU extension to OpenPGP and other implementations can not be expected to
successfully import such a key. Its intended use is in generating a full key with an additional
signing subkey on a dedicated machine. This command then exports the key without the primary key
to the main machine.
GnuPG may ask you to enter the passphrase for the key. This is required, because the internal
protection method of the secret key is different from the one specified by the OpenPGP protocol.
--export-ssh-key
This command is used to export a key in the OpenSSH public key format. It requires the
specification of one key by the usual means and exports the latest valid subkey which has an
authentication capability to STDOUT or to the file given with option --output. That output can
directly be added to ssh's ‘authorized_key’ file.
By specifying the key to export using a key ID or a fingerprint suffixed with an exclamation mark
(!), a specific subkey or the primary key can be exported. This does not even require that the
key has the authentication capability flag set.
--import
--fast-import
Import/merge keys. This adds the given keys to the keyring. The fast version is currently just a
synonym.
There are a few other options which control how this command works. Most notable here is the
--import-options merge-only option which does not insert new keys but does only the merging of new
signatures, user-IDs and subkeys.
--receive-keys keyIDs
--recv-keys keyIDs
Import the keys with the given keyIDs from a keyserver.
--refresh-keys
Request updates from a keyserver for keys that already exist on the local keyring. This is useful
for updating a key with the latest signatures, user IDs, etc. Calling this with no arguments will
refresh the entire keyring.
--search-keys names
Search the keyserver for the given names. Multiple names given here will be joined together to
create the search string for the keyserver. Note that keyservers search for names in a different
and simpler way than gpg does. The best choice is to use a mail address. Due to data privacy
reasons keyservers may even not even allow searching by user id or mail address and thus may only
return results when being used with the --recv-key command to search by key fingerprint or keyid.
--fetch-keys URIs
Retrieve keys located at the specified URIs. Note that different installations of GnuPG may
support different protocols (HTTP, FTP, LDAP, etc.). When using HTTPS the system provided root
certificates are used by this command.
--update-trustdb
Do trust database maintenance. This command iterates over all keys and builds the Web of Trust.
This is an interactive command because it may have to ask for the "ownertrust" values for keys.
The user has to give an estimation of how far she trusts the owner of the displayed key to
correctly certify (sign) other keys. GnuPG only asks for the ownertrust value if it has not yet
been assigned to a key. Using the --edit-key menu, the assigned value can be changed at any time.
--check-trustdb
Do trust database maintenance without user interaction. From time to time the trust database must
be updated so that expired keys or signatures and the resulting changes in the Web of Trust can be
tracked. Normally, GnuPG will calculate when this is required and do it automatically unless
--no-auto-check-trustdb is set. This command can be used to force a trust database check at any
time. The processing is identical to that of --update-trustdb but it skips keys with a not yet
defined "ownertrust".
For use with cron jobs, this command can be used together with --batch in which case the trust
database check is done only if a check is needed. To force a run even in batch mode add the option
--yes.
--export-ownertrust
Send the ownertrust values to STDOUT. This is useful for backup purposes as these values are the
only ones which can't be re-created from a corrupted trustdb. Example:
gpg --export-ownertrust > otrust.txt
--import-ownertrust
Update the trustdb with the ownertrust values stored in files (or STDIN if not given); existing
values will be overwritten. In case of a severely damaged trustdb and if you have a recent backup
of the ownertrust values (e.g. in the file ‘otrust.txt’), you may re-create the trustdb using
these commands:
cd ~/.gnupg
rm trustdb.gpg
gpg --import-ownertrust < otrust.txt
--rebuild-keydb-caches
When updating from version 1.0.6 to 1.0.7 this command should be used to create signature caches
in the keyring. It might be handy in other situations too.
--print-md algo
--print-mds
Print message digest of algorithm algo for all given files or STDIN. With the second form (or a
deprecated "*" for algo) digests for all available algorithms are printed.
--gen-random 0|1|2|16|30 count
Emit count random bytes of the given quality level 0, 1 or 2. If count is not given or zero, an
endless sequence of random bytes will be emitted. If used with --armor the output will be base64
encoded. The special level 16 uses a quality level of 1 and outputs an endless stream of hex-
encoded octets. The special level 30 outputs random as 30 zBase-32 characters.
--gen-prime mode bits
Use the source, Luke :-). The output format is subject to change with any release.
--enarmor
--dearmor
Pack or unpack an arbitrary input into/from an OpenPGP ASCII armor. This is a GnuPG extension to
OpenPGP and in general not very useful. The --dearmor command can also be used to dearmor PEM
armors.
--unwrap
This option modifies the command --decrypt to output the original message with the encryption
layer removed. Thus the output will be an OpenPGP data structure which often means a signed
OpenPGP message. Note that this option may or may not remove a compression layer which is often
found beneath the encryption layer.
--tofu-policy {auto|good|unknown|bad|ask} keys
Set the TOFU policy for all the bindings associated with the specified keys. For more information
about the meaning of the policies, see: [trust-model-tofu]. The keys may be specified either by
their fingerprint (preferred) or their keyid.
How to manage your keys
This section explains the main commands for key management.
--quick-generate-key user-id [algo [usage [expire]]]
--quick-gen-key
This is a simple command to generate a standard key with one user id. In contrast to
--generate-key the key is generated directly without the need to answer a bunch of prompts.
Unless the option --yes is given, the key creation will be canceled if the given user id already
exists in the keyring.
If invoked directly on the console without any special options an answer to a ``Continue?'' style
confirmation prompt is required. In case the user id already exists in the keyring a second
prompt to force the creation of the key will show up.
If algo or usage are given, only the primary key is created and no prompts are shown. To specify
an expiration date but still create a primary and subkey use ``default'' or ``future-default'' for
algo and ``default'' for usage. For a description of these optional arguments see the command
--quick-add-key. The usage accepts also the value ``cert'' which can be used to create a
certification only primary key; the default is to a create certification and signing key.
The expire argument can be used to specify an expiration date for the key. Several formats are
supported; commonly the ISO formats ``YYYY-MM-DD'' or ``YYYYMMDDThhmmss'' are used. To make the
key expire in N seconds, N days, N weeks, N months, or N years use ``seconds=N'', ``Nd'', ``Nw'',
``Nm'', or ``Ny'' respectively. Not specifying a value, or using ``-'' results in a key expiring
in a reasonable default interval. The values ``never'', ``none'' can be used for no expiration
date.
If this command is used with --batch, --pinentry-mode has been set to loopback, and one of the
passphrase options (--passphrase, --passphrase-fd, or --passphrase-file) is used, the supplied
passphrase is used for the new key and the agent does not ask for it. To create a key without any
protection --passphrase '' may be used.
To create an OpenPGP key from the keys available on the currently inserted smartcard, the special
string ``card'' can be used for algo. If the card features an encryption and a signing key, gpg
will figure them out and creates an OpenPGP key consisting of the usual primary key and one
subkey. This works only with certain smartcards. Note that the interactive --full-gen-key
command allows one to do the same but with greater flexibility in the selection of the smartcard
keys.
Note that it is possible to create a primary key and a subkey using non-default algorithms by
using ``default'' and changing the default parameters using the option --default-new-key-algo.
--quick-set-expire fpr expire [*|subfprs]
With two arguments given, directly set the expiration time of the primary key identified by fpr to
expire. To remove the expiration time 0 can be used. With three arguments and the third given as
an asterisk, the expiration time of all non-revoked and not yet expired subkeys are set to expire.
With more than two arguments and a list of fingerprints given for subfprs, all non-revoked subkeys
matching these fingerprints are set to expire.
--quick-add-key fpr [algo [usage [expire]]]
Directly add a subkey to the key identified by the fingerprint fpr. Without the optional
arguments an encryption subkey is added. If any of the arguments are given a more specific subkey
is added.
algo may be any of the supported algorithms or curve names given in the format as used by key
listings. To use the default algorithm the string ``default'' or ``-'' can be used. Supported
algorithms are ``rsa'', ``dsa'', ``elg'', ``ed25519'', ``cv25519'', and other ECC curves. For
example the string ``rsa'' adds an RSA key with the default key length; a string ``rsa4096''
requests that the key length is 4096 bits. The string ``future-default'' is an alias for the
algorithm which will likely be used as default algorithm in future versions of gpg. To list the
supported ECC curves the command gpg --with-colons --list-config curve can be used.
Depending on the given algo the subkey may either be an encryption subkey or a signing subkey. If
an algorithm is capable of signing and encryption and such a subkey is desired, a usage string
must be given. This string is either ``default'' or ``-'' to keep the default or a comma
delimited list (or space delimited list) of keywords: ``sign'' for a signing subkey, ``auth'' for
an authentication subkey, and ``encr'' for an encryption subkey (``encrypt'' can be used as alias
for ``encr''). The valid combinations depend on the algorithm.
The expire argument can be used to specify an expiration date for the key. Several formats are
supported; commonly the ISO formats ``YYYY-MM-DD'' or ``YYYYMMDDThhmmss'' are used. To make the
key expire in N seconds, N days, N weeks, N months, or N years use ``seconds=N'', ``Nd'', ``Nw'',
``Nm'', or ``Ny'' respectively. Not specifying a value, or using ``-'' results in a key expiring
in a reasonable default interval. The values ``never'', ``none'' can be used for no expiration
date.
--quick-add-adsk fpr adskfpr
Directly add an Additional Decryption Subkey to the key identified by the fingerprint fpr.
adskfpr is the fingerprint of another key's encryption subkey. A subkey is commonly used here
because by default a primary key has no encryption capability. Use the option
--with-subkey-fingerprint with a list command to display the subkey fingerprints. If the string
"default" is used for adskfpr all missing ADSKs configured with --default-new-key-adsk are added.
--generate-key
--gen-key
Generate a new key pair using the current default parameters. This is the standard command to
create a new key. In addition to the key a revocation certificate is created and stored in the
‘openpgp-revocs.d’ directory below the GnuPG home directory.
--full-generate-key
--full-gen-key
Generate a new key pair with dialogs for all options. This is an extended version of
--generate-key.
There is also a feature which allows you to create keys in batch mode. See the manual section
``Unattended key generation'' on how to use this.
--generate-revocation name
--gen-revoke name
Generate a revocation certificate for the complete key. To only revoke a subkey or a key
signature, use the --edit command.
This command merely creates the revocation certificate so that it can be used to revoke the key if
that is ever needed. To actually revoke a key the created revocation certificate needs to be
merged with the key to revoke. This is done by importing the revocation certificate using the
--import command. Then the revoked key needs to be published, which is best done by sending the
key to a keyserver (command --send-key) and by exporting (--export) it to a file which is then
send to frequent communication partners.
--generate-designated-revocation name
--desig-revoke name
Generate a designated revocation certificate for a key. This allows a user (with the permission of
the keyholder) to revoke someone else's key.
--edit-key
Present a menu which enables you to do most of the key management related tasks. It expects the
specification of a key on the command line.
uid n Toggle selection of user ID or photographic user ID with index n. Use * to select all and
0 to deselect all.
key n Toggle selection of subkey with index n or key ID n. Use * to select all and 0 to deselect
all.
sign Make a signature on key of user name. If the key is not yet signed by the default user (or
the users given with -u), the program displays the information of the key again, together
with its fingerprint and asks whether it should be signed. This question is repeated for
all users specified with -u.
lsign Same as "sign" but the signature is marked as non-exportable and will therefore never be
used by others. This may be used to make keys valid only in the local environment.
nrsign Same as "sign" but the signature is marked as non-revocable and can therefore never be
revoked.
tsign Make a trust signature. This is a signature that combines the notions of certification
(like a regular signature), and trust (like the "trust" command). It is generally useful in
distinct communities or groups to implement the concept of a Trusted Introducer. For more
information please read the sections ``Trust Signature'' and ``Regular Expression'' in
RFC-4880.
Note that "l" (for local / non-exportable), "nr" (for non-revocable, and "t" (for trust) may be
freely mixed and prefixed to "sign" to create a signature of any type desired.
If the option --only-sign-text-ids is specified, then any non-text based user ids (e.g., photo IDs) will
not be selected for signing.
delsig Delete a signature. Note that it is not possible to retract a signature, once it has been
send to the public (i.e. to a keyserver). In that case you better use revsig.
revsig Revoke a signature. For every signature which has been generated by one of the secret keys,
GnuPG asks whether a revocation certificate should be generated.
check Check the signatures on all selected user IDs. With the extra option selfsig only self-
signatures are shown.
adduid Create an additional user ID.
addphoto
Create a photographic user ID. This will prompt for a JPEG file that will be embedded into
the user ID. Note that a very large JPEG will make for a very large key. Also note that
some programs will display your JPEG unchanged (GnuPG), and some programs will scale it to
fit in a dialog box (PGP).
showphoto
Display the selected photographic user ID.
deluid Delete a user ID or photographic user ID. Note that it is not possible to retract a user
id, once it has been send to the public (i.e. to a keyserver). In that case you better use
revuid.
revuid Revoke a user ID or photographic user ID.
primary
Flag the current user id as the primary one, removes the primary user id flag from all
other user ids and sets the timestamp of all affected self-signatures one second ahead.
Note that setting a photo user ID as primary makes it primary over other photo user IDs,
and setting a regular user ID as primary makes it primary over other regular user IDs.
keyserver
Set a preferred keyserver for the specified user ID(s). This allows other users to know
where you prefer they get your key from. See --keyserver-options honor-keyserver-url for
more on how this works. Setting a value of "none" removes an existing preferred keyserver.
notation
Set a name=value notation for the specified user ID(s). See --cert-notation for more on how
this works. Setting a value of "none" removes all notations, setting a notation prefixed
with a minus sign (-) removes that notation, and setting a notation name (without the
=value) prefixed with a minus sign removes all notations with that name.
pref List preferences from the selected user ID. This shows the actual preferences, without
including any implied preferences.
showpref
More verbose preferences listing for the selected user ID. This shows the preferences in
effect by including the implied preferences of 3DES (cipher), SHA-1 (digest), and
Uncompressed (compression) if they are not already included in the preference list. In
addition, the preferred keyserver and signature notations (if any) are shown.
setpref string
Set the list of user ID preferences to string for all (or just the selected) user IDs.
Calling setpref with no arguments sets the preference list to the default (either built-in
or set via --default-preference-list), and calling setpref with "none" as the argument sets
an empty preference list. Use gpg --version to get a list of available algorithms. Note
that while you can change the preferences on an attribute user ID (aka "photo ID"), GnuPG
does not select keys via attribute user IDs so these preferences will not be used by GnuPG.
Note that an unattended version of this command is available as --quick-update-pref.
When setting preferences, you should list the algorithms in the order which you'd like to
see them used by someone else when encrypting a message to your key. If you don't include
3DES, it will be automatically added at the end. Note that there are many factors that go
into choosing an algorithm (for example, your key may not be the only recipient), and so
the remote OpenPGP application being used to send to you may or may not follow your exact
chosen order for a given message. It will, however, only choose an algorithm that is
present on the preference list of every recipient key. See also the INTEROPERABILITY WITH
OTHER OPENPGP PROGRAMS section below.
addkey Add a subkey to this key.
addcardkey
Generate a subkey on a card and add it to this key.
keytocard
Transfer the selected secret subkey (or the primary key if no subkey has been selected) to
a smartcard. The secret key in the keyring will be replaced by a stub if the key could be
stored successfully on the card and you use the save command later. Only certain key types
may be transferred to the card. A sub menu allows you to select on what card to store the
key. Note that it is not possible to get that key back from the card - if the card gets
broken your secret key will be lost unless you have a backup somewhere.
bkuptocard file
Restore the given file to a card. This command may be used to restore a backup key (as
generated during card initialization) to a new card. In almost all cases this will be the
encryption key. You should use this command only with the corresponding public key and make
sure that the file given as argument is indeed the backup to restore. You should then
select 2 to restore as encryption key. You will first be asked to enter the passphrase of
the backup key and then for the Admin PIN of the card.
keytotpm
Transfer the selected secret subkey (or the primary key if no subkey has been selected) to
TPM form. The secret key in the keyring will be replaced by the TPM representation of that
key, which can only be read by the particular TPM that created it (so the keyfile now
becomes locked to the laptop containing the TPM). Only certain key types may be
transferred to the TPM (all TPM 2.0 systems are mandated to have the rsa2048 and nistp256
algorithms but newer TPMs may have more). Note that the key itself is not transferred into
the TPM, merely encrypted by the TPM in-place, so if the keyfile is deleted, the key will
be lost. Once transferred to TPM representation, the key file can never be converted back
to non-TPM form and the key will die when the TPM does, so you should first have a backup
on secure offline storage of the actual secret key file before conversion. It is essential
to use the physical system TPM that you have rw permission on the TPM resource manager
device (/dev/tpmrm0). Usually this means you must be a member of the tss group.
delkey Remove a subkey (secondary key). Note that it is not possible to retract a subkey, once it
has been send to the public (i.e. to a keyserver). In that case you better use revkey.
Also note that this only deletes the public part of a key.
revkey Revoke a subkey.
expire Change the key or subkey expiration time. If a subkey is selected, the expiration time of
this subkey will be changed. With no selection, the key expiration of the primary key is
changed.
trust Change the owner trust value for the key. This updates the trust-db immediately and no save
is required.
disable
enable Disable or enable an entire key. A disabled key can not normally be used for encryption.
addrevoker
Add a designated revoker to the key. This takes one optional argument: "sensitive". If a
designated revoker is marked as sensitive, it will not be exported by default (see export-
options).
addadsk
Add an Additional Decryption Subkey. The user is asked to enter the fingerprint of another
encryption subkey. Note that the exact fingerprint of another key's encryption subkey
needs to be entered. This is because commonly the primary key has no encryption
capability. Use the option --with-subkey-fingerprint with a list command to display the
subkey fingerprints.
passwd Change the passphrase of the secret key.
toggle This is dummy command which exists only for backward compatibility.
clean Compact (by removing all signatures except the selfsig) any user ID that is no longer
usable (e.g. revoked, or expired). Then, remove any signatures that are not usable by the
trust calculations. Specifically, this removes any signature that does not validate, any
signature that is superseded by a later signature, revoked signatures, and signatures
issued by keys that are not present on the keyring.
minimize
Make the key as small as possible. This removes all signatures from each user ID except for
the most recent self-signature.
change-usage
Change the usage flags (capabilities) of the primary key or of subkeys. These usage flags
(e.g. Certify, Sign, Authenticate, Encrypt) are set during key creation. Sometimes it is
useful to have the opportunity to change them (for example to add Authenticate) after they
have been created. Please take care when doing this; the allowed usage flags depend on the
key algorithm.
cross-certify
Add cross-certification signatures to signing subkeys that may not currently have them.
Cross-certification signatures protect against a subtle attack against signing subkeys. See
--require-cross-certification. All new keys generated have this signature by default, so
this command is only useful to bring older keys up to date.
save Save all changes to the keyring and quit.
quit Quit the program without updating the keyring.
The listing shows you the key with its secondary keys and all user IDs. The primary user ID is
indicated by a dot, and selected keys or user IDs are indicated by an asterisk. The trust value
is displayed with the primary key: "trust" is the assigned owner trust and "validity" is the
calculated validity of the key. Validity values are also displayed for all user IDs. For
possible values of trust, see: [trust-values].
--sign-key name
Signs a public key with your secret key. This is a shortcut version of the subcommand "sign" from
--edit-key.
--lsign-key name
Signs a public key with your secret key but marks it as non-exportable. This is a shortcut version
of the subcommand "lsign" from --edit-key.
--quick-sign-key fpr [names]
--quick-lsign-key fpr [names]
Directly sign a key from the passphrase without any further user interaction. The fpr must be the
verified primary fingerprint of a key in the local keyring. If no names are given, all useful user
ids are signed; with given [names] only useful user ids matching one of these names are signed.
By default, or if a name is prefixed with a '*', a case insensitive substring match is used. If a
name is prefixed with a '=' a case sensitive exact match is done.
The command --quick-lsign-key marks the signatures as non-exportable. If such a non-exportable
signature already exists the --quick-sign-key turns it into a exportable signature. If you need
to update an existing signature, for example to add or change notation data, you need to use the
option --force-sign-key.
This command uses reasonable defaults and thus does not provide the full flexibility of the "sign"
subcommand from --edit-key. Its intended use is to help unattended key signing by utilizing a
list of verified fingerprints.
--quick-add-uid user-id new-user-id
This command adds a new user id to an existing key. In contrast to the interactive sub-command
adduid of --edit-key the new-user-id is added verbatim with only leading and trailing white space
removed, it is expected to be UTF-8 encoded, and no checks on its form are applied.
--quick-revoke-uid user-id user-id-to-revoke
This command revokes a user ID on an existing key. It cannot be used to revoke the last user ID
on key (some non-revoked user ID must remain), with revocation reason ``User ID is no longer
valid''. If you want to specify a different revocation reason, or to supply supplementary
revocation text, you should use the interactive sub-command revuid of --edit-key.
--quick-revoke-sig fpr signing-fpr [names]
This command revokes the key signatures made by signing-fpr from the key specified by the
fingerprint fpr. With names given only the signatures on user ids of the key matching any of the
given names are affected (see --quick-sign-key). If a revocation already exists a notice is
printed instead of creating a new revocation; no error is returned in this case. Note that key
signature revocations may be superseded by a newer key signature and in turn again revoked.
--quick-set-primary-uid user-id primary-user-id
This command sets or updates the primary user ID flag on an existing key. user-id specifies the
key and primary-user-id the user ID which shall be flagged as the primary user ID. The primary
user ID flag is removed from all other user ids and the timestamp of all affected self-signatures
is set one second ahead.
--quick-update-pref user-id
This command updates the preference list of the key to the current default value (either built-in
or set via --default-preference-list). This is the unattended version of using "setpref" in the
--key-edit menu without giving a list. Note that you can show the preferences in a key listing by
using --list-options show-pref or --list-options show-pref-verbose. You should also re-distribute
updated keys to your peers.
--quick-set-ownertrust user-id value
This command sets the ownertrust of a key and can also be used to set the disable flag of a key.
This is the unattended version of using "trust", "disable", or "enable" in the --key-edit menu.
--change-passphrase user-id
--passwd user-id
Change the passphrase of the secret key belonging to the certificate specified as user-id. This
is a shortcut for the sub-command passwd of the --edit-key menu. When using together with the
option --dry-run this will not actually change the passphrase but check that the current
passphrase is correct.
OPTIONS
gpg features a bunch of options to control the exact behaviour and to change the default configuration.
Long options can be put in an options file (default "~/.gnupg/gpg.conf"). Short option names will not
work - for example, "armor" is a valid option for the options file, while "a" is not. Do not write the 2
dashes, but simply the name of the option and any required arguments. Lines with a hash ('#') as the
first non-white-space character are ignored. Commands may be put in this file too, but that is not
generally useful as the command will execute automatically with every execution of gpg.
Please remember that option parsing stops as soon as a non-option is encountered, you can explicitly stop
parsing by using the special option --.
How to change the configuration
These options are used to change the configuration and most of them are usually found in the option file.
--default-key name
Use name as the default key to sign with. It is suggested to use a fingerprint or at least a long
keyID for name. If this option is not used, the default key is the first key found in the secret
keyring. Note that -u or --local-user overrides this option. This option may be given multiple
times. In this case, the last key for which a secret key is available is used. If there is no
secret key available for any of the specified values, GnuPG will not emit an error message but
continue as if this option wasn't given.
--default-recipient name
Use name as default recipient if option --recipient is not used and don't ask if this is a valid
one. name must be non-empty and it is suggested to use a fingerprint for name.
--default-recipient-self
Use the default key as default recipient if option --recipient is not used and don't ask if this
is a valid one. The default key is the first one from the secret keyring or the one set with
--default-key.
--no-default-recipient
Reset --default-recipient and --default-recipient-self. Should not be used in an option file.
-v, --verbose
Give more information during processing. If used twice, the input data is listed in detail.
--no-verbose
Reset verbose level to 0. Should not be used in an option file.
-q, --quiet
Try to be as quiet as possible. Should not be used in an option file.
--batch
--no-batch
Use batch mode. Never ask, do not allow interactive commands. --no-batch disables this option.
Note that even with a filename given on the command line, gpg might still need to read from STDIN
(in particular if gpg figures that the input is a detached signature and no data file has been
specified). Thus if you do not want to feed data via STDIN, you should connect STDIN to
‘/dev/null’.
It is highly recommended to use this option along with the options --status-fd and --with-colons
for any unattended use of gpg. Should not be used in an option file.
--no-tty
Make sure that the TTY (terminal) is never used for any output. This option is needed in some
cases because GnuPG sometimes prints warnings to the TTY even if --batch is used.
--yes Assume "yes" on most questions. Should not be used in an option file.
--no Assume "no" on most questions. Should not be used in an option file.
--proc-all-sigs
This option overrides the behaviour of the --batch option to stop signature verification at the
first bad signatures.
--list-filter {select=expr}
A list filter can be used to output only certain keys during key listing commands. For the
available property names, see the description of --import-filter.
--list-options parameters
This is a space or comma delimited string that gives options used when listing keys and signatures
(that is, --list-keys, --check-signatures, --list-public-keys, --list-secret-keys, and the
--edit-key functions). Options can be prepended with a no- (after the two dashes) to give the
opposite meaning. The options are:
show-photos
Causes --list-keys, --check-signatures, --list-public-keys, and --list-secret-keys to
display any photo IDs attached to the key. Defaults to no. See also --photo-viewer. Does
not work with --with-colons: see --attribute-fd for the appropriate way to get photo data
for scripts and other frontends.
show-usage
Show usage information for keys and subkeys in the standard key listing. This is a list of
letters indicating the allowed usage for a key (E=encryption, S=signing, C=certification,
A=authentication). Defaults to yes.
show-ownertrust
Show the ownertrust value for keys also in the standard key listing. Defaults to no.
show-policy-urls
Show policy URLs in the --check-signatures listings. Defaults to no.
show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature notations in the --check-signatures
listings. Defaults to no.
show-keyserver-urls
Show any preferred keyserver URL in the --check-signatures listings. Defaults to no.
show-uid-validity
Display the calculated validity of user IDs during key listings. Defaults to yes.
show-unusable-uids
Show revoked and expired user IDs in key listings. Defaults to no.
show-unusable-subkeys
Show revoked and expired subkeys in key listings. Defaults to no.
show-unusable-sigs
Show key signature made using weak or unsupported algorithms.
show-keyring
Display the keyring name at the head of key listings to show which keyring a given key
resides on. Defaults to no.
show-sig-expire
Show signature expiration dates (if any) during --check-signatures listings. Defaults to
no.
show-sig-subpackets
Include signature subpackets in the key listing. This option can take an optional argument
list of the subpackets to list. If no argument is passed, list all subpackets. Defaults to
no. This option is only meaningful when using --with-colons along with --check-signatures.
show-only-fpr-mbox
For each user-id which has a valid mail address print only the fingerprint followed by the
mail address.
sort-sigs
With --list-sigs and --check-sigs sort the signatures by keyID and creation time to make it
easier to view the history of these signatures. The self-signature is also listed before
other signatures. Defaults to yes. This option has no effect in -with-colons mode.
--verify-options parameters
This is a space or comma delimited string that gives options used when verifying signatures.
Options can be prepended with a `no-' to give the opposite meaning. The options are:
show-photos
Display any photo IDs present on the key that issued the signature. Defaults to no. See
also --photo-viewer.
show-policy-urls
Show policy URLs in the signature being verified. Defaults to yes.
show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature notations in the signature being
verified. Defaults to IETF standard.
show-keyserver-urls
Show any preferred keyserver URL in the signature being verified. Defaults to yes.
show-uid-validity
Display the calculated validity of the user IDs on the key that issued the signature.
Defaults to yes.
show-unusable-uids
Show revoked and expired user IDs during signature verification. Defaults to no.
show-primary-uid-only
Show only the primary user ID during signature verification. That is all the AKA lines as
well as photo Ids are not shown with the signature verification status.
--enable-large-rsa
--disable-large-rsa
Enable the creation of RSA secret keys as large as 8192 bit. Note: 8192 bit is more than is
generally recommended. These large keys don't significantly improve security, but they are more
expensive to use, and their signatures and certifications are larger. This option is only
available if the binary was build with large-secmem support.
--enable-dsa2
--disable-dsa2
Enable hash truncation for all DSA keys even for old DSA Keys up to 1024 bit. This is also the
default with --openpgp. Note that older versions of GnuPG also required this flag to allow the
generation of DSA larger than 1024 bit.
--photo-viewer string
This is the command line that should be run to view a photo ID. "%i" will be expanded to a
filename containing the photo. "%I" does the same, except the file will not be deleted once the
viewer exits. Other flags are "%k" for the key ID, "%K" for the long key ID, "%f" for the key
fingerprint, "%t" for the extension of the image type (e.g. "jpg"), "%T" for the MIME type of the
image (e.g. "image/jpeg"), "%v" for the single-character calculated validity of the image being
viewed (e.g. "f"), "%V" for the calculated validity as a string (e.g. "full"), "%U" for a base32
encoded hash of the user ID, and "%%" for an actual percent sign. If neither %i or %I are present,
then the photo will be supplied to the viewer on standard input.
On Unix the default viewer is xloadimage -fork -quiet -title 'KeyID 0x%k' STDIN with a fallback to
display -title 'KeyID 0x%k' %i and finally to xdg-open %i. On Windows !ShellExecute 400 %i is
used; here the command is a meta command to use that API call followed by a wait time in
milliseconds which is used to give the viewer time to read the temporary image file before gpg
deletes it again. Note that if your image viewer program is not secure, then executing it from
gpg does not make it secure.
--exec-path string
Sets a list of directories to search for photo viewers If not provided photo viewers use the PATH
environment variable.
--keyring file
Add file to the current list of keyrings. If file begins with a tilde and a slash, these are
replaced by the $HOME directory. If the filename does not contain a slash, it is assumed to be in
the GnuPG home directory ("~/.gnupg" unless --homedir or $GNUPGHOME is used).
Note that this adds a keyring to the current list. If the intent is to use the specified keyring
alone, use --keyring along with --no-default-keyring.
If the option --no-keyring has been used no keyrings will be used at all.
Note that if the option use-keyboxd is enabled in ‘common.conf’, no keyrings are used at all and
keys are all maintained by the keyboxd process in its own database.
--primary-keyring file
This is a varian of --keyring and designates file as the primary public keyring. This means that
newly imported keys (via --import or keyserver --recv-from) will go to this keyring.
--secret-keyring file
This is an obsolete option and ignored. All secret keys are stored in the ‘private-keys-v1.d’
directory below the GnuPG home directory.
--trustdb-name file
Use file instead of the default trustdb. If file begins with a tilde and a slash, these are
replaced by the $HOME directory. If the filename does not contain a slash, it is assumed to be in
the GnuPG home directory (‘~/.gnupg’ if --homedir or $GNUPGHOME is not used).
--homedir dir
Set the name of the home directory to dir. If this option is not used, the home directory defaults
to ‘~/.gnupg’. It is only recognized when given on the command line. It also overrides any home
directory stated through the environment variable ‘GNUPGHOME’ or (on Windows systems) by means of
the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.
On Windows systems it is possible to install GnuPG as a portable application. In this case only
this command line option is considered, all other ways to set a home directory are ignored.
--display-charset name
Set the name of the native character set. This is used to convert some informational strings like
user IDs to the proper UTF-8 encoding. Note that this has nothing to do with the character set of
data to be encrypted or signed; GnuPG does not recode user-supplied data. If this option is not
used, the default character set is determined from the current locale. A verbosity level of 3
shows the chosen set. This option should not be used on Windows. Valid values for name are:
iso-8859-1
This is the Latin 1 set.
iso-8859-2
The Latin 2 set.
iso-8859-15
This is currently an alias for the Latin 1 set.
koi8-r The usual Russian set (RFC-1489).
utf-8 Bypass all translations and assume that the OS uses native UTF-8 encoding.
--utf8-strings
--no-utf8-strings
Assume that command line arguments are given as UTF-8 strings. The default (--no-utf8-strings) is
to assume that arguments are encoded in the character set as specified by --display-charset. These
options affect all following arguments. Both options may be used multiple times. This option
should not be used in an option file.
This option has no effect on Windows. There the internal used UTF-8 encoding is translated for
console input and output. The command line arguments are expected as Unicode and translated to
UTF-8. Thus when calling this program from another, make sure to use the Unicode version of
CreateProcess.
--options file
Read options from file and do not try to read them from the default options file in the homedir
(see --homedir). This option is ignored if used in an options file.
--no-options
Shortcut for --options /dev/null. This option is detected before an attempt to open an option
file. Using this option will also prevent the creation of a ‘~/.gnupg’ homedir.
-z n
--compress-level n
--bzip2-compress-level n
--no-compress
Set compression level to n for the ZIP and ZLIB compression algorithms. The default is to use the
default compression level of zlib (normally 6). --bzip2-compress-level sets the compression level
for the BZIP2 compression algorithm (defaulting to 6 as well). This is a different option from
--compress-level since BZIP2 uses a significant amount of memory for each additional compression
level.
Option -z sets both. A value of 0 for n disables compression. A value of -1 forces compression
using the default level. Option --no-compress is identical to -z0.
Except for the --store command compression is always used unless gpg detects that the input is
already compressed. To inhibit the use of compression use -z0 or --no-compress; to force
compression use -z-1 or option z with another compression level than the default as indicated by
-1. Note that this overriding of the default deection works only with z and not with the long
variant of this option.
--bzip2-decompress-lowmem
Use a different decompression method for BZIP2 compressed files. This alternate method uses a bit
more than half the memory, but also runs at half the speed. This is useful under extreme low
memory circumstances when the file was originally compressed at a high --bzip2-compress-level.
--mangle-dos-filenames
--no-mangle-dos-filenames
Older version of Windows cannot handle filenames with more than one dot. --mangle-dos-filenames
causes GnuPG to replace (rather than add to) the extension of an output filename to avoid this
problem. This option is off by default and has no effect on non-Windows platforms.
--ask-cert-level
--no-ask-cert-level
When making a key signature, prompt for a certification level. If this option is not specified,
the certification level used is set via --default-cert-level. See --default-cert-level for
information on the specific levels and how they are used. --no-ask-cert-level disables this
option. This option defaults to no.
--default-cert-level n
The default to use for the check level when signing a key.
0 means you make no particular claim as to how carefully you verified the key.
1 means you believe the key is owned by the person who claims to own it but you could not, or did
not verify the key at all. This is useful for a "persona" verification, where you sign the key of
a pseudonymous user.
2 means you did casual verification of the key. For example, this could mean that you verified the
key fingerprint and checked the user ID on the key against a photo ID.
3 means you did extensive verification of the key. For example, this could mean that you verified
the key fingerprint with the owner of the key in person, and that you checked, by means of a hard
to forge document with a photo ID (such as a passport) that the name of the key owner matches the
name in the user ID on the key, and finally that you verified (by exchange of email) that the
email address on the key belongs to the key owner.
Note that the examples given above for levels 2 and 3 are just that: examples. In the end, it is
up to you to decide just what "casual" and "extensive" mean to you.
This option defaults to 0 (no particular claim).
--min-cert-level
When building the trust database, treat any signatures with a certification level below this as
invalid. Defaults to 2, which disregards level 1 signatures. Note that level 0 "no particular
claim" signatures are always accepted.
--trusted-key long key ID or fingerprint
Assume that the specified key (which should be given as fingerprint) is as trustworthy as one of
your own secret keys. This option is useful if you don't want to keep your secret keys (or one of
them) online but still want to be able to check the validity of a given recipient's or signator's
key. If the given key is not locally available but an LDAP keyserver is configured the missing
key is imported from that server. The value "none" is explicitly allowed to distinguish between
the use of any trusted-key option and no use of this option at all (e.g. due to the --no-options
option).
--add-desig-revoker [sensitive:]fingerprint
Add the key specified by fingerprint as a designated revoker to newly created keys. If the
fingerprint is prefixed with the keyword ``sensitive:'' that info is normally not exported with
the key. This option may be given several times to add more than one designated revoker. If the
keyword ``clear'' is used instead of a fingerprint, all previously fiven fingerprints are
discarded. Designated revokers are marked on the key as non-revocable. Note that a designated
revoker specified using a parameter file will also be added to the key.
--default-new-key-adsk fingerprint
Add the subkey specified by fingerprint as an Additional Decryption Subkey (ADSK) to newly created
keys. This option may be given several time to add more than one ADSK. It is also possible to
give several fingerprints delimited by space or comma as value to this option. If the keyword
``clear'' is used instead of a fingerprint, all previously specified fingerprints are discarded
(useful to override options given in a config file). The fingerprint is expected to specify a
subkey and it does not need an exclamation mark as suffix; it must be given in cmpact format (40
or 64 hex-digits without any spaces).
--trust-model {pgp|classic|tofu|tofu+pgp|direct|always|auto}
Set what trust model GnuPG should follow. The models are:
pgp This is the Web of Trust combined with trust signatures as used in PGP 5.x and later. This
is the default trust model when creating a new trust database.
classic
This is the standard Web of Trust as introduced by PGP 2.
tofu
TOFU stands for Trust On First Use. In this experimental trust model, the first time a key
is seen, it is memorized. If later another key with a user id with the same email address
is seen, both keys are marked as suspect. In that case, the next time either is used, a
warning is displayed describing the conflict, why it might have occurred (either the user
generated a new key and failed to cross sign the old and new keys, the key is forgery, or a
man-in-the-middle attack is being attempted), and the user is prompted to manually confirm
the validity of the key in question.
Because a potential attacker is able to control the email address and thereby circumvent
the conflict detection algorithm by using an email address that is similar in appearance to
a trusted email address, whenever a message is verified, statistics about the number of
messages signed with the key are shown. In this way, a user can easily identify attacks
using fake keys for regular correspondents.
When compared with the Web of Trust, TOFU offers significantly weaker security guarantees.
In particular, TOFU only helps ensure consistency (that is, that the binding between a key
and email address doesn't change). A major advantage of TOFU is that it requires little
maintenance to use correctly. To use the web of trust properly, you need to actively sign
keys and mark users as trusted introducers. This is a time-consuming process and anecdotal
evidence suggests that even security-conscious users rarely take the time to do this
thoroughly and instead rely on an ad-hoc TOFU process.
In the TOFU model, policies are associated with bindings between keys and email addresses
(which are extracted from user ids and normalized). There are five policies, which can be
set manually using the --tofu-policy option. The default policy can be set using the
--tofu-default-policy option.
The TOFU policies are: auto, good, unknown, bad and ask. The auto policy is used by
default (unless overridden by --tofu-default-policy) and marks a binding as marginally
trusted. The good, unknown and bad policies mark a binding as fully trusted, as having
unknown trust or as having trust never, respectively. The unknown policy is useful for
just using TOFU to detect conflicts, but to never assign positive trust to a binding. The
final policy, ask prompts the user to indicate the binding's trust. If batch mode is
enabled (or input is inappropriate in the context), then the user is not prompted and the
undefined trust level is returned.
tofu+pgp
This experimental trust model combines TOFU with the Web of Trust. This is done by
computing the trust level for each model and then taking the maximum trust level where the
trust levels are ordered as follows: unknown < undefined < marginal < fully < ultimate <
expired < never.
By setting --tofu-default-policy=unknown, this model can be used to implement the web of
trust with TOFU's conflict detection algorithm, but without its assignment of positive
trust values, which some security-conscious users don't like.
direct Key validity is set directly by the user and not calculated via the Web of Trust. This
model is solely based on the key and does not distinguish user IDs. Note that when
changing to another trust model the trust values assigned to a key are transformed into
ownertrust values, which also indicate how you trust the owner of the key to sign other
keys.
always Skip key validation and assume that used keys are always fully valid. You generally won't
use this unless you are using some external validation scheme. This option also suppresses
the "[uncertain]" tag printed with signature checks when there is no evidence that the user
ID is bound to the key. Note that this trust model still does not allow the use of
expired, revoked, or disabled keys.
auto Select the trust model depending on whatever the internal trust database says. This is the
default model if such a database already exists. Note that a tofu trust model is not
considered here and must be enabled explicitly.
--always-trust
Identical to --trust-model always.
--assert-signer fpr_or_file
This option checks whether at least one valid signature on a file has been made with the specified
key. The key is either specified as a fingerprint or a file listing fingerprints. The
fingerprint must be given or listed in compact format (no colons or spaces in between). This
option can be given multiple times and each fingerprint is checked against the signing key as well
as the corresponding primary key. If fpr_or_file specifies a file, empty lines are ignored as
well as all lines starting with a hash sign. With this option gpg is guaranteed to return with an
exit code of 0 if and only if a signature has been encountered, is valid, and the key matches one
of the fingerprints given by this option.
--assert-pubkey-algo algolist
During data signature verification this options checks whether the used public key algorithm
matches the algorithms given by algolist. This option can be given multiple times to concatenate
more algorithms to the list; the delimiter of the list are either commas or spaces.
The algorithm names given in the list may either be verbatim names like "ed25519" with an optional
leading single equal sign, or being prefixed with ">", ">=", "<=", or "<". That prefix operator
is applied to the number part of the algorithm name; for example 2048 in "rsa2048" or 384 in
"brainpoolP384r1". If the the leading non-digits in the name matches, the prefix operator is used
to compare the number part, a trailing suffix is ignored in this case. For example an algorithm
list ">rsa3000, >=brainpool384r1, =ed25519" allows RSA signatures with more that 3000 bits,
Brainpool curves 384 and 512, and the ed25519 algorithm.
With this option gpg (and also gpgv) is guaranteed to return with an exit code of 0 if and only if
all valid signatures on data are made using a matching algorithm from the given list.
--auto-key-locate mechanisms
--no-auto-key-locate
GnuPG can automatically locate and retrieve keys as needed using this option. This happens when
encrypting to an email address (in the "user@example.com" form), and there are no
"user@example.com" keys on the local keyring. This option takes any number of the mechanisms
listed below, in the order they are to be tried. Instead of listing the mechanisms as comma
delimited arguments, the option may also be given several times to add more mechanism. The option
--no-auto-key-locate or the mechanism "clear" resets the list. The default is "local,wkd".
cert Locate a key using DNS CERT, as specified in RFC-4398.
dane Locate a key using DANE, as specified in draft-ietf-dane-openpgpkey-05.txt.
wkd Locate a key using the Web Key Directory protocol.
ldap Locate the key using the configured LDAP servers. This method is similar to the keyserver
mechanism but always uses only LDAP servers.
ntds Locate the key using the Active Directory (Windows only). This method also allows one to
search by fingerprint using the command --locate-external-key. Note that this mechanism is
actually a shortcut for the mechanism ‘ldap’ using only "ldap:///" as the keyserver.
keyserver
Locate a key using a keyserver. This method also allows one to search by fingerprint using
the command --locate-external-key if any of the configured keyservers is an LDAP server.
keyserver-URL
In addition, a keyserver URL as used in the dirmngr configuration may be used here to query
that particular keyserver. This method also allows one to search by fingerprint using the
command --locate-external-key if the URL specifies an LDAP server.
local Locate the key using the local keyrings. This mechanism allows the user to select the
order a local key lookup is done. Thus using ‘--auto-key-locate local’ is identical to
--no-auto-key-locate.
nodefault
This flag disables the standard local key lookup, done before any of the mechanisms defined
by the --auto-key-locate are tried. The position of this mechanism in the list does not
matter. It is not required if local is also used.
clear Clear all defined mechanisms. This is useful to override mechanisms given in a config
file. Note that a nodefault in mechanisms will also be cleared unless it is given after
the clear.
--auto-key-import
--no-auto-key-import
This is an offline mechanism to get a missing key for signature verification and for later
encryption to this key. If this option is enabled and a signature includes an embedded key, that
key is used to verify the signature and on verification success the key is imported. The default
is --no-auto-key-import.
On the sender (signing) site the option --include-key-block needs to be used to put the public
part of the signing key as “Key Block subpacket” into the signature.
--auto-key-retrieve
--no-auto-key-retrieve
These options enable or disable the automatic retrieving of keys from a keyserver when verifying
signatures made by keys that are not on the local keyring. The default is --no-auto-key-retrieve.
The order of methods tried to lookup the key is:
1. If the option --auto-key-import is set and the signatures includes an embedded key, that key is
used to verify the signature and on verification success that key is imported.
2. If a preferred keyserver is specified in the signature and the option honor-keyserver-url is
active (which is not the default), that keyserver is tried. Note that the creator of the
signature uses the option --sig-keyserver-url to specify the preferred keyserver for data
signatures.
3. If the signature has the Signer's UID set (e.g. using --sender while creating the signature) a
Web Key Directory (WKD) lookup is done. This is the default configuration but can be disabled by
removing WKD from the auto-key-locate list or by using the option --disable-signer-uid.
4. If any keyserver is configured and the Issuer Fingerprint is part of the signature (since GnuPG
2.1.16), the configured keyservers are tried.
Note that this option makes a "web bug" like behavior possible. Keyserver or Web Key Directory
operators can see which keys you request, so by sending you a message signed by a brand new key
(which you naturally will not have on your local keyring), the operator can tell both your IP
address and the time when you verified the signature.
--keyid-format {none|short|0xshort|long|0xlong}
Select how to display key IDs. "none" does not show the key ID at all but shows the fingerprint
in a separate line. "short" is the traditional 8-character key ID. "long" is the more accurate
(but less convenient) 16-character key ID. Add an "0x" to either to include an "0x" at the
beginning of the key ID, as in 0x99242560. Note that this option is ignored if the option
--with-colons is used.
--keyserver name
This option is deprecated - please use the --keyserver in ‘dirmngr.conf’ instead.
Use name as your keyserver. This is the server that --receive-keys, --send-keys, and --search-keys
will communicate with to receive keys from, send keys to, and search for keys on. The format of
the name is a URI: `scheme:[//]keyservername[:port]' The scheme is the type of keyserver:
"hkp"/"hkps" for the HTTP (or compatible) keyservers or "ldap"/"ldaps" for the LDAP keyservers.
Note that your particular installation of GnuPG may have other keyserver types available as well.
Keyserver schemes are case-insensitive.
Most keyservers synchronize with each other, so there is generally no need to send keys to more
than one server. The keyserver hkp://keys.gnupg.net uses round robin DNS to give a different
keyserver each time you use it.
--keyserver-options {name=value}
This is a space or comma delimited string that gives options for the keyserver. Options can be
prefixed with a `no-' to give the opposite meaning. Valid import-options or export-options may be
used here as well to apply to importing (--recv-key) or exporting (--send-key) a key from a
keyserver. While not all options are available for all keyserver types, some common options are:
include-revoked
When searching for a key with --search-keys, include keys that are marked on the keyserver
as revoked. Note that not all keyservers differentiate between revoked and unrevoked keys,
and for such keyservers this option is meaningless. Note also that most keyservers do not
have cryptographic verification of key revocations, and so turning this option off may
result in skipping keys that are incorrectly marked as revoked.
include-disabled
When searching for a key with --search-keys, include keys that are marked on the keyserver
as disabled. Note that this option is not used with HKP keyservers.
auto-key-retrieve
This is an obsolete alias for the option auto-key-retrieve. Please do not use it; it will
be removed in future versions..
honor-keyserver-url
When using --refresh-keys, if the key in question has a preferred keyserver URL, then use
that preferred keyserver to refresh the key from. In addition, if auto-key-retrieve is set,
and the signature being verified has a preferred keyserver URL, then use that preferred
keyserver to fetch the key from. Note that this option introduces a "web bug": The creator
of the key can see when the keys is refreshed. Thus this option is not enabled by default.
include-subkeys
When receiving a key, include subkeys as potential targets. Note that this option is not
used with HKP keyservers, as they do not support retrieving keys by subkey id.
only-pubkeys
Do now allow to import secret keys.
timeout
http-proxy=value
verbose
debug
check-cert
ca-cert-file
These options have no more function since GnuPG 2.1. Use the dirmngr configuration options
instead.
The default list of options is: "self-sigs-only, repair-keys, repair-pks-subkey-bug, export-attributes".
However, if the actual used source is an LDAP server "no-self-sigs-only" is assumed unless "self-sigs-
only" has been explicitly configured.
--completes-needed n
Number of completely trusted users to introduce a new key signer (defaults to 1).
--marginals-needed n
Number of marginally trusted users to introduce a new key signer (defaults to 3)
--tofu-default-policy {auto|good|unknown|bad|ask}
The default TOFU policy (defaults to auto). For more information about the meaning of this
option, see: [trust-model-tofu].
--max-cert-depth n
Maximum depth of a certification chain (default is 5).
--no-sig-cache
Do not cache the verification status of key signatures. Caching gives a much better performance
in key listings. However, if you suspect that your public keyring is not safe against write
modifications, you can use this option to disable the caching. It probably does not make sense to
disable it because all kind of damage can be done if someone else has write access to your public
keyring.
--auto-check-trustdb
--no-auto-check-trustdb
If GnuPG feels that its information about the Web of Trust has to be updated, it automatically
runs the --check-trustdb command internally. This may be a time consuming process.
--no-auto-check-trustdb disables this option.
--use-agent
--no-use-agent
This is dummy option. gpg always requires the agent.
--gpg-agent-info
This is dummy option. It has no effect when used with gpg.
--agent-program file
Specify an agent program to be used for secret key operations. The default value is determined by
running gpgconf with the option --list-dirs. Note that the pipe symbol (|) is used for a
regression test suite hack and may thus not be used in the file name.
--dirmngr-program file
Specify a dirmngr program to be used for keyserver access. The default value is
‘/usr/bin/dirmngr’.
--disable-dirmngr
Entirely disable the use of the Dirmngr.
--no-autostart
Do not start the gpg-agent or the dirmngr if it has not yet been started and its service is
required. This option is mostly useful on machines where the connection to gpg-agent has been
redirected to another machines. If dirmngr is required on the remote machine, it may be started
manually using gpgconf --launch dirmngr.
--lock-once
Lock the databases the first time a lock is requested and do not release the lock until the
process terminates.
--lock-multiple
Release the locks every time a lock is no longer needed. Use this to override a previous
--lock-once from a config file.
--lock-never
Disable locking entirely. This option should be used only in very special environments, where it
can be assured that only one process is accessing those files. A bootable floppy with a stand-
alone encryption system will probably use this. Improper usage of this option may lead to data and
key corruption.
--exit-on-status-write-error
This option will cause write errors on the status FD to immediately terminate the process. That
should in fact be the default but it never worked this way and thus we need an option to enable
this, so that the change won't break applications which close their end of a status fd connected
pipe too early. Using this option along with --enable-progress-filter may be used to cleanly
cancel long running gpg operations.
--limit-card-insert-tries n
With n greater than 0 the number of prompts asking to insert a smartcard gets limited to N-1. Thus
with a value of 1 gpg won't at all ask to insert a card if none has been inserted at startup. This
option is useful in the configuration file in case an application does not know about the
smartcard support and waits ad infinitum for an inserted card.
--no-random-seed-file
GnuPG uses a file to store its internal random pool over invocations. This makes random
generation faster; however sometimes write operations are not desired. This option can be used to
achieve that with the cost of slower random generation.
--no-greeting
Suppress the initial copyright message.
--no-secmem-warning
Suppress the warning about "using insecure memory".
--no-permission-warning
Suppress the warning about unsafe file and home directory (--homedir) permissions. Note that the
permission checks that GnuPG performs are not intended to be authoritative, but rather they simply
warn about certain common permission problems. Do not assume that the lack of a warning means that
your system is secure.
Note that the warning for unsafe --homedir permissions cannot be suppressed in the gpg.conf file,
as this would allow an attacker to place an unsafe gpg.conf file in place, and use this file to
suppress warnings about itself. The --homedir permissions warning may only be suppressed on the
command line.
--require-secmem
--no-require-secmem
Refuse to run if GnuPG cannot get secure memory. Defaults to no (i.e. run, but give a warning).
--require-cross-certification
--no-require-cross-certification
When verifying a signature made from a subkey, ensure that the cross certification "back
signature" on the subkey is present and valid. This protects against a subtle attack against
subkeys that can sign. Defaults to --require-cross-certification for gpg.
--expert
--no-expert
Allow the user to do certain nonsensical or "silly" things like signing an expired or revoked key,
or certain potentially incompatible things like generating unusual key types. This also disables
certain warning messages about potentially incompatible actions. As the name implies, this option
is for experts only. If you don't fully understand the implications of what it allows you to do,
leave this off. --no-expert disables this option.
Key related options
--recipient name
-r Encrypt for user id name. If this option or --hidden-recipient is not specified, GnuPG asks for
the user-id unless --default-recipient is given.
--hidden-recipient name
-R Encrypt for user ID name, but hide the key ID of this user's key. This option helps to hide the
receiver of the message and is a limited countermeasure against traffic analysis. If this option
or --recipient is not specified, GnuPG asks for the user ID unless --default-recipient is given.
--recipient-file file
-f This option is similar to --recipient except that it encrypts to a key stored in the given file.
file must be the name of a file containing exactly one key. gpg assumes that the key in this file
is fully valid.
--hidden-recipient-file file
-F This option is similar to --hidden-recipient except that it encrypts to a key stored in the given
file. file must be the name of a file containing exactly one key. gpg assumes that the key in
this file is fully valid.
--encrypt-to name
Same as --recipient but this one is intended for use in the options file and may be used with your
own user-id as an "encrypt-to-self". It is suggested to use a fingerprint or at least a long
keyID for name. These keys are only used when there are other recipients given either by use of
--recipient or by the asked user id. No trust checking is performed for these user ids and even
disabled keys can be used.
--hidden-encrypt-to name
Same as --hidden-recipient but this one is intended for use in the options file and may be used
with your own user-id as a hidden "encrypt-to-self". It is suggested to use a fingerprint or at
least a long keyID for name. These keys are only used when there are other recipients given
either by use of --recipient or by the asked user id. No trust checking is performed for these
user ids and even disabled keys can be used.
--no-encrypt-to
Disable the use of all --encrypt-to and --hidden-encrypt-to keys.
--group {name=value}
Sets up a named group, which is similar to aliases in email programs. Any time the group name is
a recipient (-r or --recipient), it will be expanded to the values specified. Multiple groups with
the same name are automatically merged into a single group.
The values are key IDs or fingerprints, but any key description is accepted. Note that a value
with spaces in it will be treated as two different values. Note also there is only one level of
expansion --- you cannot make an group that points to another group. When used from the command
line, it may be necessary to quote the argument to this option to prevent the shell from treating
it as multiple arguments.
--ungroup name
Remove a given entry from the --group list.
--no-groups
Remove all entries from the --group list.
--local-user name
-u Use name as the key to sign with. Note that this option overrides --default-key.
--sender mbox
This option has two purposes. mbox must either be a complete user ID containing a proper mail
address or just a plain mail address. The option can be given multiple times.
When creating a signature this option tells gpg the signing key's user id used to make the
signature and embeds that user ID into the created signature (using OpenPGP's ``Signer's User ID''
subpacket). If the option is given multiple times a suitable user ID is picked. However, if the
signing key was specified directly by using a mail address (i.e. not by using a fingerprint or key
ID) this option is used and the mail address is embedded in the created signature.
When verifying a signature mbox is used to restrict the information printed by the TOFU code to
matching user IDs. If the option is used and the signature contains a ``Signer's User ID''
subpacket that information is is also used to restrict the printed information. Note that GnuPG
considers only the mail address part of a User ID.
If this option or the said subpacket is available the TRUST lines as printed by option status-fd
correspond to the corresponding User ID; if no User ID is known the TRUST lines are computed
directly on the key and do not give any information about the User ID. In the latter case it his
highly recommended to scripts and other frontends to evaluate the VALIDSIG line, retrieve the key
and print all User IDs along with their validity (trust) information.
--try-secret-key name
For hidden recipients GPG needs to know the keys to use for trial decryption. The key set with
--default-key is always tried first, but this is often not sufficient. This option allows setting
more keys to be used for trial decryption. Although any valid user-id specification may be used
for name it makes sense to use at least the long keyid to avoid ambiguities. Note that gpg-agent
might pop up a pinentry for a lot keys to do the trial decryption. If you want to stop all
further trial decryption you may use close-window button instead of the cancel button.
--try-all-secrets
Don't look at the key ID as stored in the message but try all secret keys in turn to find the
right decryption key. This option forces the behaviour as used by anonymous recipients (created by
using --throw-keyids or --hidden-recipient) and might come handy in case where an encrypted
message contains a bogus key ID.
--skip-hidden-recipients
--no-skip-hidden-recipients
During decryption skip all anonymous recipients. This option helps in the case that people use
the hidden recipients feature to hide their own encrypt-to key from others. If one has many
secret keys this may lead to a major annoyance because all keys are tried in turn to decrypt
something which was not really intended for it. The drawback of this option is that it is
currently not possible to decrypt a message which includes real anonymous recipients.
Input and Output
--armor
-a Create ASCII armored output. The default is to create the binary OpenPGP format.
--no-armor
Assume the input data is not in ASCII armored format.
--output file
-o file
Write output to file. To write to stdout use - as the filename.
--max-output n
This option sets a limit on the number of bytes that will be generated when processing a file.
Since OpenPGP supports various levels of compression, it is possible that the plaintext of a given
message may be significantly larger than the original OpenPGP message. While GnuPG works properly
with such messages, there is often a desire to set a maximum file size that will be generated
before processing is forced to stop by the OS limits. Defaults to 0, which means "no limit".
--chunk-size n
The AEAD encryption mode encrypts the data in chunks so that a receiving side can check for
transmission errors or tampering at the end of each chunk and does not need to delay this until
all data has been received. The used chunk size is 2^n byte. The lowest allowed value for n is 6
(64 byte) and the largest is the default of 22 which creates chunks not larger than 4 MiB.
--input-size-hint n
This option can be used to tell GPG the size of the input data in bytes. n must be a positive
base-10 number. This option is only useful if the input is not taken from a file. GPG may use
this hint to optimize its buffer allocation strategy. It is also used by the --status-fd line
``PROGRESS'' to provide a value for ``total'' if that is not available by other means.
--key-origin string[,url]
gpg can track the origin of a key. Certain origins are implicitly known (e.g. keyserver, web key
directory) and set. For a standard import the origin of the keys imported can be set with this
option. To list the possible values use "help" for string. Some origins can store an optional
url argument. That URL can appended to string after a comma.
--import-options parameters
This is a space or comma delimited string that gives options for importing keys. Options can be
prepended with a `no-' to give the opposite meaning. The options are:
import-local-sigs
Allow importing key signatures marked as "local". This is not generally useful unless a
shared keyring scheme is being used. Defaults to no.
keep-ownertrust
Normally possible still existing ownertrust values of a key are cleared if a key is
imported. This is in general desirable so that a formerly deleted key does not
automatically gain an ownertrust values merely due to import. On the other hand it is
sometimes necessary to re-import a trusted set of keys again but keeping already assigned
ownertrust values. This can be achieved by using this option.
repair-pks-subkey-bug
During import, attempt to repair the damage caused by the PKS keyserver bug (pre version
0.9.6) that mangles keys with multiple subkeys. Note that this cannot completely repair the
damaged key as some crucial data is removed by the keyserver, but it does at least give you
back one subkey. Defaults to no for regular --import and to yes for keyserver
--receive-keys.
import-show
show-only
Show a listing of the key as imported right before it is stored. This can be combined with
the option --dry-run to only look at keys; the option show-only is a shortcut for this
combination. The command --show-keys is another shortcut for this. Note that suffixes
like '#' for "sec" and "sbb" lines may or may not be printed.
import-export
Run the entire import code but instead of storing the key to the local keyring write it to
the output. The export option export-dane affect the output. This option can for example
be used to remove all invalid parts from a key without the need to store it.
merge-only
During import, allow key updates to existing keys, but do not allow any new keys to be
imported. Defaults to no.
import-clean
After import, compact (remove all signatures except the self-signature) any user IDs from
the new key that are not usable. Then, remove any signatures from the new key that are not
usable. This includes signatures that were issued by keys that are not present on the
keyring. This option is the same as running the --edit-key command "clean" after import.
Defaults to no.
self-sigs-only
Accept only self-signatures while importing a key. All other key signatures are skipped at
an early import stage. This option can be used with keyserver-options to mitigate attempts
to flood a key with bogus signatures from a keyserver. The drawback is that all other
valid key signatures, as required by the Web of Trust are also not imported. Note that
when using this option along with import-clean it suppresses the final clean step after
merging the imported key into the existing key.
ignore-attributes
Ignore all attribute user IDs (photo IDs) and their signatures while importing a key.
repair-keys
After import, fix various problems with the keys. For example, this reorders signatures,
and strips duplicate signatures. Defaults to yes.
bulk-import
When used the keyboxd (option use-keyboxd in ‘common.conf’) does the import within a single
transaction.
import-minimal
Import the smallest key possible. This removes all signatures except the most recent self-
signature on each user ID. This option is the same as running the --edit-key command
"minimize" after import. Defaults to no.
restore
import-restore
Import in key restore mode. This imports all data which is usually skipped during import;
including all GnuPG specific data. All other contradicting options are overridden.
--import-filter {name=expr}
--export-filter {name=expr}
These options define an import/export filter which are applied to the imported/exported keyblock
right before it will be stored/written. name defines the type of filter to use, expr the
expression to evaluate. The option can be used several times which then appends more expression
to the same name.
The available filter types are:
keep-uid
This filter will keep a user id packet and its dependent packets in the keyblock if the
expression evaluates to true.
drop-subkey
This filter drops the selected subkeys. Currently only implemented for --export-filter.
drop-sig
This filter drops the selected key signatures on user ids. Self-signatures are not
considered. Currently only implemented for --import-filter.
select This filter is only implemented by --list-filter. All property names may be used.
For the syntax of the expression see the chapter "FILTER EXPRESSIONS". The property names for the
expressions depend on the actual filter type and are indicated in the following table. Note that all
property names may also be used by --list-filter.
Property names may be prefix with a scope delimited by a slash. Valid scopes are "pub" for public and
secret primary keys, "sub" for public and secret subkeys, "uid" for for user-ID packets, and "sig" for
signature packets. Invalid scopes are currently ignored.
The available properties are:
uid A string with the user id. (keep-uid)
mbox The addr-spec part of a user id with mailbox or the empty string. (keep-uid)
algostr
A string with the key algorithm description. For example "rsa3072" or "ed25519".
key_algo
A number with the public key algorithm of a key or subkey packet. (drop-subkey)
key_size
A number with the effective key size of a key or subkey packet. (drop-subkey)
key_created
key_created_d
The first is the timestamp a public key or subkey packet was created. The second is the
same but given as an ISO string, e.g. "2016-08-17". (drop-subkey)
key_expires
key_expires_d
The expiration time of a public key or subkey or 0 if it does not expire. The second is
the same but given as an ISO date string or an empty string e.g. "2038-01-19".
fpr The hexified fingerprint of the current subkey or primary key. (drop-subkey)
primary
Boolean indicating whether the user id is the primary one. (keep-uid)
expired
Boolean indicating whether a user id (keep-uid), a key (drop-subkey), or a signature (drop-
sig) expired.
revoked
Boolean indicating whether a user id (keep-uid) or a key (drop-subkey) has been revoked.
disabled
Boolean indicating whether a primary key is disabled.
secret Boolean indicating whether a key or subkey is a secret one. (drop-subkey)
usage A string indicating the usage flags for the subkey, from the sequence ``ecsa?''. For
example, a subkey capable of just signing and authentication would be an exact match for
``sa''. (drop-subkey)
sig_created
sig_created_d
The first is the timestamp a signature packet was created. The second is the same but
given as an ISO date string, e.g. "2016-08-17". (drop-sig)
sig_expires
sig_expires_d
The expiration time of a signature packet or 0 if it does not expire. The second is the
same but given as an ISO date string or an empty string e.g. "2038-01-19".
sig_algo
A number with the public key algorithm of a signature packet. (drop-sig)
sig_digest_algo
A number with the digest algorithm of a signature packet. (drop-sig)
origin A string with the key origin or a question mark. For example the string ``wkd'' is used if
a key originated from a Web Key Directory lookup.
lastupd
The timestamp the key was last updated from a keyserver or the Web Key Directory.
url A string with the the URL associated wit the last key lookup.
--export-options parameters
This is a space or comma delimited string that gives options for exporting keys. Options can be
prepended with a `no-' to give the opposite meaning. The options are:
export-local-sigs
Allow exporting key signatures marked as "local". This is not generally useful unless a
shared keyring scheme is being used. Defaults to no.
export-attributes
Include attribute user IDs (photo IDs) while exporting. Not including attribute user IDs is
useful to export keys that are going to be used by an OpenPGP program that does not accept
attribute user IDs. Defaults to yes.
export-sensitive-revkeys
Include designated revoker information that was marked as "sensitive". Defaults to no.
backup
export-backup
Export for use as a backup. The exported data includes all data which is needed to restore
the key or keys later with GnuPG. The format is basically the OpenPGP format but enhanced
with GnuPG specific data. All other contradicting options are overridden.
export-clean
Compact (remove all signatures from) user IDs on the key being exported if the user IDs are
not usable. Also, do not export any signatures that are not usable. This includes
signatures that were issued by keys that are not present on the keyring. This option is the
same as running the --edit-key command "clean" before export except that the local copy of
the key is not modified. Defaults to no.
export-minimal
Export the smallest key possible. This removes all signatures except the most recent self-
signature on each user ID. This option is the same as running the --edit-key command
"minimize" before export except that the local copy of the key is not modified. Defaults to
no.
export-revocs
Export only standalone revocation certificates of the key. This option does not export
revocations of 3rd party certificate revocations.
export-dane
Instead of outputting the key material output OpenPGP DANE records suitable to put into DNS
zone files. An ORIGIN line is printed before each record to allow diverting the records to
the corresponding zone file.
mode1003
Enable the use of a new secret key export format. This format avoids the re-encryption as
required with the current OpenPGP format and also improves the security of the secret key
if it has been protected with a passphrase. Note that an unprotected key is exported as-is
and thus not secure; the general rule to convey secret keys in an OpenPGP encrypted file
still applies with this mode. Versions of GnuPG before 2.4.0 are not able to import such a
secret file.
--with-colons
Print key listings delimited by colons. Note that the output will be encoded in UTF-8 regardless
of any --display-charset setting. This format is useful when GnuPG is called from scripts and
other programs as it is easily machine parsed. The details of this format are documented in the
file ‘doc/DETAILS’, which is included in the GnuPG source distribution.
--fixed-list-mode
Do not merge primary user ID and primary key in --with-colon listing mode and print all timestamps
as seconds since 1970-01-01. Since GnuPG 2.0.10, this mode is always used and thus this option is
obsolete; it does not harm to use it though.
--legacy-list-mode
Revert to the pre-2.1 public key list mode. This only affects the human readable output and not
the machine interface (i.e. --with-colons). Note that the legacy format does not convey suitable
information for elliptic curves.
--with-fingerprint
Same as the command --fingerprint but changes only the format of the output and may be used
together with another command.
--with-subkey-fingerprint
If a fingerprint is printed for the primary key, this option forces printing of the fingerprint
for all subkeys. This could also be achieved by using the --with-fingerprint twice but by using
this option along with keyid-format "none" a compact fingerprint is printed.
--with-v5-fingerprint
In a colon mode listing emit "fp2" lines for version 4 OpenPGP keys having a v5 style fingerprint
of the key.
--with-icao-spelling
Print the ICAO spelling of the fingerprint in addition to the hex digits.
--with-keygrip
Include the keygrip in the key listings. In --with-colons mode this is implicitly enable for
secret keys.
--with-key-origin
Include the locally held information on the origin and last update of a key in a key listing. In
--with-colons mode this is always printed. This data is currently experimental and shall not be
considered part of the stable API.
--with-wkd-hash
Print a Web Key Directory identifier along with each user ID in key listings. This is an
experimental feature and semantics may change.
--with-secret
Include info about the presence of a secret key in public key listings done with --with-colons.
OpenPGP protocol specific options
--force-ocb
--force-aead
Force the use of AEAD encryption over MDC encryption. AEAD is a modern and faster way to do
authenticated encryption than the old MDC method. --force-aead is an alias and deprecated. See
also option --chunk-size.
--force-mdc
--disable-mdc
These options are obsolete and have no effect since GnuPG 2.2.8. The MDC is always used unless
the keys indicate that an AEAD algorithm can be used in which case AEAD is used. But note: If the
creation of a legacy non-MDC message is exceptionally required, the option --rfc2440 allows for
this.
--disable-signer-uid
By default the user ID of the signing key is embedded in the data signature. As of now this is
only done if the signing key has been specified with local-user using a mail address, or with
sender. This information can be helpful for verifier to locate the key; see option
--auto-key-retrieve.
--include-key-block
--no-include-key-block
This option is used to embed the actual signing key into a data signature. The embedded key is
stripped down to a single user id and includes only the signing subkey used to create the
signature as well as as valid encryption subkeys. All other info is removed from the key to keep
it and thus the signature small. This option is the OpenPGP counterpart to the gpgsm option
--include-certs and allows the recipient of a signed message to reply encrypted to the sender
without using any online directories to lookup the key. The default is --no-include-key-block.
See also the option --auto-key-import.
--personal-cipher-preferences string
Set the list of personal cipher preferences to string. Use gpg --version to get a list of
available algorithms, and use none to set no preference at all. This allows the user to safely
override the algorithm chosen by the recipient key preferences, as GPG will only select an
algorithm that is usable by all recipients. The most highly ranked cipher in this list is also
used for the --symmetric encryption command.
--personal-digest-preferences string
Set the list of personal digest preferences to string. Use gpg --version to get a list of
available algorithms, and use none to set no preference at all. This allows the user to safely
override the algorithm chosen by the recipient key preferences, as GPG will only select an
algorithm that is usable by all recipients. The most highly ranked digest algorithm in this list
is also used when signing without encryption (e.g. --clear-sign or --sign).
--personal-compress-preferences string
Set the list of personal compression preferences to string. Use gpg --version to get a list of
available algorithms, and use none to set no preference at all. This allows the user to safely
override the algorithm chosen by the recipient key preferences, as GPG will only select an
algorithm that is usable by all recipients. The most highly ranked compression algorithm in this
list is also used when there are no recipient keys to consider (e.g. --symmetric).
--s2k-cipher-algo name
Use name as the cipher algorithm for symmetric encryption with a passphrase if
--personal-cipher-preferences and --cipher-algo are not given. The default is AES-128.
--s2k-digest-algo name
Use name as the digest algorithm used to mangle the passphrases for symmetric encryption. The
default is SHA-1.
--s2k-mode n
Selects how passphrases for symmetric encryption are mangled. If n is 0 a plain passphrase (which
is in general not recommended) will be used, a 1 adds a salt (which should not be used) to the
passphrase and a 3 (the default) iterates the whole process a number of times (see --s2k-count).
--s2k-count n
Specify how many times the passphrases mangling for symmetric encryption is repeated. This value
may range between 1024 and 65011712 inclusive. The default is inquired from gpg-agent. Note that
not all values in the 1024-65011712 range are legal and if an illegal value is selected, GnuPG
will round up to the nearest legal value. This option is only meaningful if --s2k-mode is set to
the default of 3.
Compliance options
These options control what GnuPG is compliant to. Only one of these options may be active at a time. If
multiple options are given, the last one supersedes all the others. Note that the default setting of this
is nearly always the correct one. See the INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS section below
before using one of these options.
--gnupg
Use standard GnuPG behavior. This is now LibrePGP behavior, which is a different draft protocol
that overlaps in some cases with OpenPGP.
--openpgp
Set all packet, cipher and digest options to OpenPGP compatible (RFC-9580) behavior. Note that
not all of RFC-9580 is implemented by GnuPG. This is the default option, so it is not generally
needed, but it may be useful to override a different compliance option in the gpg.conf file.
--rfc4880
Set all packet, cipher and digest options to strict RFC-4880 behavior. RFC-4880 is the legacy
version of the OpenPGP standard. This option implies --allow-old-cipher-algos.
--rfc4880bis
This option is obsolete; it is handled as an alias for --gnupg.
--rfc2440
Set all packet, cipher and digest options to strict RFC-2440 behavior. RFC-2440 is a very old
version of OpenPGP. Note that by using this option encryption packets are created in a legacy
mode without MDC protection. This is dangerous and should thus only be used for experiments.
This option implies --allow-old-cipher-algos. See also option --ignore-mdc-error.
--pgp6 This option is obsolete; it is handled as an alias for --pgp7.
--pgp7 Set up all options to be as PGP 7 compliant as possible. This allowed the ciphers IDEA, 3DES,
CAST5,AES128, AES192, AES256, and TWOFISH., the hashes MD5, SHA1 and RIPEMD160, and the
compression algorithms none and ZIP. This option implies --escape-from-lines and disables
--throw-keyids,
--pgp8 Set up all options to be as PGP 8 compliant as possible. PGP 8 is a lot closer to the OpenPGP
standard than previous versions of PGP, so all this does is disable --throw-keyids and set
--escape-from-lines. All algorithms are allowed except for the SHA224, SHA384, and SHA512
digests.
--compliance string
This option can be used instead of one of the options above. Valid values for string are the
above option names (without the double dash) and possibly others as shown when using "help" for
string.
--min-rsa-length n
This option adjusts the compliance mode "de-vs" for stricter key size requirements. For example,
a value of 3000 turns rsa2048 and dsa2048 keys into non-VS-NfD compliant keys.
--require-compliance
To check that data has been encrypted according to the rules of the current compliance mode, a gpg
user needs to evaluate the status lines. This is allows frontends to handle compliance check in a
more flexible way. However, for scripted use the required evaluation of the status-line requires
quite some effort; this option can be used instead to make sure that the gpg process exits with a
failure if the compliance rules are not fulfilled. Note that this option has currently an effect
only in "de-vs" mode.
Doing things one usually doesn't want to do
-n
--dry-run
Don't make any changes (this is not completely implemented).
--list-only
Changes the behaviour of some commands. This is like --dry-run but different in some cases. The
semantic of this option may be extended in the future. Currently it only skips the actual
decryption pass and therefore enables a fast listing of the encryption keys.
-i
--interactive
Prompt before overwriting any files.
--compatibility-flags flags
Set compatibility flags to work around problems due to non-compliant keys or data. The flags are
given as a comma separated list of flag names and are OR-ed together. The special flag "none"
clears the list and allows one to start over with an empty list. To get a list of available flags
the sole word "help" can be used.
--debug-level level
Select the debug level for investigating problems. level may be a numeric value or by a keyword:
none No debugging at all. A value of less than 1 may be used instead of the keyword.
basic Some basic debug messages. A value between 1 and 2 may be used instead of the keyword.
advanced
More verbose debug messages. A value between 3 and 5 may be used instead of the keyword.
expert Even more detailed messages. A value between 6 and 8 may be used instead of the keyword.
guru All of the debug messages you can get. A value greater than 8 may be used instead of the
keyword. The creation of hash tracing files is only enabled if the keyword is used.
How these messages are mapped to the actual debugging flags is not specified and may change with newer
releases of this program. They are however carefully selected to best aid in debugging.
--debug flags
Set debug flags. All flags are or-ed and flags may be given in C syntax (e.g. 0x0042) or as a
comma separated list of flag names. To get a list of all supported flags the single word "help"
can be used. This option is only useful for debugging and the behavior may change at any time
without notice.
--debug-all
Set all useful debugging flags.
--debug-iolbf
Set stdout into line buffered mode. This option is only honored when given on the command line.
--debug-set-iobuf-size n
Change the buffer size of the IOBUFs to n kilobyte. Using 0 prints the current size. Note well:
This is a maintainer only option and may thus be changed or removed at any time without notice.
--debug-allow-large-chunks
To facilitate software tests and experiments this option allows one to specify a limit of up to 4
EiB (--chunk-size 62).
--debug-ignore-expiration
This option tries to override certain key expiration dates. It is only useful for certain
regression tests.
--faked-system-time epoch
This option is only useful for testing; it sets the system time back or forth to epoch which is
the number of seconds elapsed since the year 1970. Alternatively epoch may be given as a full ISO
time string (e.g. "20070924T154812").
If you suffix epoch with an exclamation mark (!), the system time will appear to be frozen at the
specified time.
--full-timestrings
Change the format of printed creation and expiration times from just the date to the date and
time. This is in general not useful and the same information is anyway available in --with-colons
mode. These longer strings are also not well aligned with other printed data.
--enable-progress-filter
Enable certain PROGRESS status outputs. This option allows frontends to display a progress
indicator while gpg is processing larger files. There is a slight performance overhead using it.
--status-fd n
Write special status strings to the file descriptor n. See the file DETAILS in the documentation
for a listing of them.
--status-file file
Same as --status-fd, except the status data is written to file file.
--logger-fd n
Write log output to file descriptor n and not to STDERR.
--log-file file
--logger-file file
Same as --logger-fd, except the logger data is written to file file. Use ‘socket://’ to log to s
socket.
--log-time
Prefix all log output with a timestamp even if no log file is used.
--attribute-fd n
Write attribute subpackets to the file descriptor n. This is most useful for use with --status-fd,
since the status messages are needed to separate out the various subpackets from the stream
delivered to the file descriptor.
--attribute-file file
Same as --attribute-fd, except the attribute data is written to file file.
--comment string
--no-comments
Use string as a comment string in cleartext signatures and ASCII armored messages or keys (see
--armor). The default behavior is not to use a comment string. --comment may be repeated multiple
times to get multiple comment strings. --no-comments removes all comments. It is a good idea to
keep the length of a single comment below 60 characters to avoid problems with mail programs
wrapping such lines. Note that comment lines, like all other header lines, are not protected by
the signature.
--emit-version
--no-emit-version
Force inclusion of the version string in ASCII armored output. If given once only the name of the
program and the major number is emitted, given twice the minor is also emitted, given thrice the
micro is added, and given four times an operating system identification is also emitted.
--no-emit-version (default) disables the version line.
--sig-notation {name=value}
--cert-notation {name=value}
-N, --set-notation {name=value}
Put the name value pair into the signature as notation data. name must consist only of printable
characters or spaces, and must contain a '@' character in the form keyname@domain.example.com
(substituting the appropriate keyname and domain name, of course). This is to help prevent
pollution of the IETF reserved notation namespace. The --expert flag overrides the '@' check.
value may be any printable string; it will be encoded in UTF-8, so you should check that your
--display-charset is set correctly. If you prefix name with an exclamation mark (!), the notation
data will be flagged as critical (rfc4880:5.2.3.16). --sig-notation sets a notation for data
signatures. --cert-notation sets a notation for key signatures (certifications). --set-notation
sets both.
There are special codes that may be used in notation names. "%k" will be expanded into the key ID
of the key being signed, "%K" into the long key ID of the key being signed, "%f" into the
fingerprint of the key being signed, "%s" into the key ID of the key making the signature, "%S"
into the long key ID of the key making the signature, "%g" into the fingerprint of the key making
the signature (which might be a subkey), "%p" into the fingerprint of the primary key of the key
making the signature, "%c" into the signature count from the OpenPGP smartcard, and "%%" results
in a single "%". %k, %K, and %f are only meaningful when making a key signature (certification),
and %c is only meaningful when using the OpenPGP smartcard.
--known-notation name
Adds name to a list of known critical signature notations. The effect of this is that gpg will
not mark a signature with a critical signature notation of that name as bad. Note that gpg
already knows by default about a few critical signatures notation names.
--sig-policy-url string
--cert-policy-url string
--set-policy-url string
Use string as a Policy URL for signatures (rfc4880:5.2.3.20). If you prefix it with an
exclamation mark (!), the policy URL packet will be flagged as critical. --sig-policy-url sets a
policy url for data signatures. --cert-policy-url sets a policy url for key signatures
(certifications). --set-policy-url sets both.
The same %-expandos used for notation data are available here as well.
--sig-keyserver-url string
Use string as a preferred keyserver URL for data signatures. If you prefix it with an exclamation
mark (!), the keyserver URL packet will be flagged as critical.
The same %-expandos used for notation data are available here as well.
--set-filename string
Use string as the filename which is stored inside messages. This overrides the default, which is
to use the actual filename of the file being encrypted. Using the empty string for string
effectively removes the filename from the output.
--for-your-eyes-only
--no-for-your-eyes-only
Set the `for your eyes only' flag in the message. This causes GnuPG to refuse to save the file
unless the --output option is given, and PGP to use a "secure viewer" with a claimed Tempest-
resistant font to display the message. This option overrides --set-filename.
--no-for-your-eyes-only disables this option.
--use-embedded-filename
--no-use-embedded-filename
Try to create a file with a name as embedded in the data. This can be a dangerous option as it
enables overwriting files by giving the sender control on how to store files. Defaults to no.
Note that the option --output overrides this option.
A better approach than using this option is to decrypt to a temporary filename and then rename
that file to the embedded file name after checking that the embedded filename is harmless. When
using the --status-fd option gpg tells the filename as part of the PLAINTEXT status message. If
the filename is important, the use of gpgtar is another option because gpgtar will never overwrite
a file but decrypt the files to a new directory.
Note also that unless a modern version 5 signature is used the embedded filename is not part of
the signed data.
--cipher-algo name
Use name as cipher algorithm. Running the program with the command --version yields a list of
supported algorithms. If this is not used the cipher algorithm is selected from the preferences
stored with the key. In general, you do not want to use this option as it allows you to violate
the OpenPGP standard. The option --personal-cipher-preferences is the safe way to accomplish the
same thing.
--digest-algo name
Use name as the message digest algorithm. Running the program with the command --version yields a
list of supported algorithms. In general, you do not want to use this option as it allows you to
violate the OpenPGP standard. The option --personal-digest-preferences is the safe way to
accomplish the same thing.
--compress-algo name
Use compression algorithm name. "zlib" is RFC-1950 ZLIB compression. "zip" is RFC-1951 ZIP
compression which is used by PGP. "bzip2" is a more modern compression scheme that can compress
some things better than zip or zlib, but at the cost of more memory used during compression and
decompression. "uncompressed" or "none" disables compression. If this option is not used, the
default behavior is to examine the recipient key preferences to see which algorithms the recipient
supports. If all else fails, ZIP is used for maximum compatibility.
ZLIB may give better compression results than ZIP, as the compression window size is not limited
to 8k. BZIP2 may give even better compression results than that, but will use a significantly
larger amount of memory while compressing and decompressing. This may be significant in low memory
situations. Note, however, that PGP (all versions) only supports ZIP compression. Using any
algorithm other than ZIP or "none" will make the message unreadable with PGP. In general, you do
not want to use this option as it allows you to violate the OpenPGP standard. The option
--personal-compress-preferences is the safe way to accomplish the same thing.
--cert-digest-algo name
Use name as the message digest algorithm used when signing a key. Running the program with the
command --version yields a list of supported algorithms. Be aware that if you choose an algorithm
that GnuPG supports but other OpenPGP implementations do not, then some users will not be able to
use the key signatures you make, or quite possibly your entire key. Note also that a public key
algorithm must be compatible with the specified digest algorithm; thus selecting an arbitrary
digest algorithm may result in error messages from lower crypto layers or lead to security flaws.
--disable-cipher-algo name
Never allow the use of name as cipher algorithm. The given name will not be checked so that a
later loaded algorithm will still get disabled.
--disable-pubkey-algo name
Never allow the use of name as public key algorithm. The given name will not be checked so that a
later loaded algorithm will still get disabled.
--throw-keyids
--no-throw-keyids
Do not put the recipient key IDs into encrypted messages. This helps to hide the receivers of the
message and is a limited countermeasure against traffic analysis. ([Using a little social
engineering anyone who is able to decrypt the message can check whether one of the other
recipients is the one he suspects.]) On the receiving side, it may slow down the decryption
process because all available secret keys must be tried. --no-throw-keyids disables this option.
This option is essentially the same as using --hidden-recipient for all recipients.
--not-dash-escaped
This option changes the behavior of cleartext signatures so that they can be used for patch files.
You should not send such an armored file via email because all spaces and line endings are hashed
too. You can not use this option for data which has 5 dashes at the beginning of a line, patch
files don't have this. A special armor header line tells GnuPG about this cleartext signature
option.
--escape-from-lines
--no-escape-from-lines
Because some mailers change lines starting with "From " to ">From " it is good to handle such
lines in a special way when creating cleartext signatures to prevent the mail system from breaking
the signature. Note that all other PGP versions do it this way too. Enabled by default.
--no-escape-from-lines disables this option.
--passphrase-repeat n
Specify how many times gpg will request a new passphrase be repeated. This is useful for helping
memorize a passphrase. Defaults to 1 repetition; can be set to 0 to disable any passphrase
repetition. Note that a n greater than 1 will pop up the pinentry window n+1 times even if a
modern pinentry with two entry fields is used.
--passphrase-fd n
Read the passphrase from file descriptor n. Only the first line will be read from file descriptor
n. If you use 0 for n, the passphrase will be read from STDIN. This can only be used if only one
passphrase is supplied.
Note that since Version 2.0 this passphrase is only used if the option --batch has also been
given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.
--passphrase-file file
Read the passphrase from file file. Only the first line will be read from file file. This can only
be used if only one passphrase is supplied. Obviously, a passphrase stored in a file is of
questionable security if other users can read this file. Don't use this option if you can avoid
it.
Note that since Version 2.0 this passphrase is only used if the option --batch has also been
given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.
--passphrase string
Use string as the passphrase. This can only be used if only one passphrase is supplied. Obviously,
this is of very questionable security on a multi-user system. Don't use this option if you can
avoid it.
Note that since Version 2.0 this passphrase is only used if the option --batch has also been
given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.
--pinentry-mode mode
Set the pinentry mode to mode. Allowed values for mode are:
default
Use the default of the agent, which is ask.
ask Force the use of the Pinentry.
cancel Emulate use of Pinentry's cancel button.
error Return a Pinentry error (``No Pinentry'').
loopback
Redirect Pinentry queries to the caller. Note that in contrast to Pinentry the user is not
prompted again if he enters a bad password.
--no-symkey-cache
Disable the passphrase cache used for symmetrical en- and decryption. This cache is based on the
message specific salt value (cf. --s2k-mode).
--request-origin origin
Tell gpg to assume that the operation ultimately originated at origin. Depending on the origin
certain restrictions are applied and the Pinentry may include an extra note on the origin.
Supported values for origin are: local which is the default, remote to indicate a remote origin or
browser for an operation requested by a web browser.
--command-fd n
This is a replacement for the deprecated shared-memory IPC mode. If this option is enabled, user
input on questions is not expected from the TTY but from the given file descriptor. It should be
used together with --status-fd. See the file doc/DETAILS in the source distribution for details on
how to use it.
--command-file file
Same as --command-fd, except the commands are read out of file file
--allow-non-selfsigned-uid
--no-allow-non-selfsigned-uid
Allow the import and use of keys with user IDs which are not self-signed. This is not recommended,
as a non self-signed user ID is trivial to forge. --no-allow-non-selfsigned-uid disables.
--allow-freeform-uid
Disable all checks on the form of the user ID while generating a new one. This option should only
be used in very special environments as it does not ensure the de-facto standard format of user
IDs.
--ignore-time-conflict
GnuPG normally checks that the timestamps associated with keys and signatures have plausible
values. However, sometimes a signature seems to be older than the key due to clock problems. This
option makes these checks just a warning. See also --ignore-valid-from for timestamp issues on
subkeys.
--ignore-valid-from
GnuPG normally does not select and use subkeys created in the future. This option allows the use
of such keys and thus exhibits the pre-1.0.7 behaviour. You should not use this option unless
there is some clock problem. See also --ignore-time-conflict for timestamp issues with signatures.
--ignore-crc-error
The ASCII armor used by OpenPGP is protected by a CRC checksum against transmission errors.
Occasionally the CRC gets mangled somewhere on the transmission channel but the actual content
(which is protected by the OpenPGP protocol anyway) is still okay. This option allows GnuPG to
ignore CRC errors.
--ignore-mdc-error
This option changes a MDC integrity protection failure into a warning. It is required to decrypt
old messages which did not use an MDC. It may also be useful if a message is partially garbled,
but it is necessary to get as much data as possible out of that garbled message. Be aware that a
missing or failed MDC can be an indication of an attack. Use with great caution; see also option
--rfc2440.
--allow-old-cipher-algos
Old cipher algorithms like 3DES, IDEA, or CAST5 encrypt data using blocks of 64 bits; modern
algorithms use blocks of 128 bit instead. To avoid certain attack on these old algorithms it is
suggested not to encrypt more than 150 MiByte using the same key. For this reason gpg does not
allow the use of 64 bit block size algorithms for encryption unless this option is specified.
Some compliance modes already set or clear this flag and thus this flag should be used after a
compliance mode setting.
--allow-weak-digest-algos
Signatures made with known-weak digest algorithms are normally rejected with an ``invalid digest
algorithm'' message. This option allows the verification of signatures made with such weak
algorithms. MD5 is the only digest algorithm considered weak by default. See also --weak-digest
to reject other digest algorithms.
--weak-digest name
Treat the specified digest algorithm as weak. Signatures made over weak digests algorithms are
normally rejected. This option can be supplied multiple times if multiple algorithms should be
considered weak. See also --allow-weak-digest-algos to disable rejection of weak digests. MD5 is
always considered weak, and does not need to be listed explicitly.
--allow-weak-key-signatures
To avoid a minor risk of collision attacks on third-party key signatures made using SHA-1, those
key signatures are considered invalid. This options allows one to override this restriction.
--override-compliance-check
This was a temporary introduced option and has no more effect.
--no-default-keyring
Do not add the default keyring to the list of keyrings. Note that GnuPG needs for almost all
operations a keyring. Thus if you use this option and do not provide alternate keyrings via
--keyring, then GnuPG will still use the default keyring.
Note that if the option use-keyboxd is enabled in ‘common.conf’, no keyrings are used at all and
keys are all maintained by the keyboxd process in its own database.
--no-keyring
Do not use any keyring at all. This overrides the default and all options which specify keyrings.
--skip-verify
Skip the signature verification step. This may be used to make the decryption faster if the
signature verification is not needed.
--with-key-data
Print key listings delimited by colons (like --with-colons) and print the public key data.
--list-signatures
--list-sigs
Same as --list-keys, but the signatures are listed too. This command has the same effect as using
--list-keys with --with-sig-list. Note that in contrast to --check-signatures the key signatures
are not verified. This command can be used to create a list of signing keys missing in the local
keyring; for example:
gpg --list-sigs --with-colons USERID | \
awk -F: '$1=="sig" && $2=="?" {if($13){print $13}else{print $5}}'
--fast-list-mode
Changes the output of the list commands to work faster; this is achieved by leaving some parts
empty. Some applications don't need the user ID and the trust information given in the listings.
By using this options they can get a faster listing. The exact behaviour of this option may change
in future versions. If you are missing some information, don't use this option.
--no-literal
This is not for normal use. Use the source to see for what it might be useful.
--set-filesize
This is not for normal use. Use the source to see for what it might be useful.
--show-session-key
Display the session key used for one message. See --override-session-key for the counterpart of
this option.
We think that Key Escrow is a Bad Thing; however the user should have the freedom to decide
whether to go to prison or to reveal the content of one specific message without compromising all
messages ever encrypted for one secret key.
You can also use this option if you receive an encrypted message which is abusive or offensive, to
prove to the administrators of the messaging system that the ciphertext transmitted corresponds to
an inappropriate plaintext so they can take action against the offending user.
--override-session-key string
--override-session-key-fd fd
Don't use the public key but the session key string respective the session key taken from the
first line read from file descriptor fd. The format of this string is the same as the one printed
by --show-session-key. This option is normally not used but comes handy in case someone forces you
to reveal the content of an encrypted message; using this option you can do this without handing
out the secret key. Note that using --override-session-key may reveal the session key to all
local users via the global process table. Often it is useful to combine this option with
--no-keyring.
--ask-sig-expire
--no-ask-sig-expire
When making a data signature, prompt for an expiration time. If this option is not specified, the
expiration time set via --default-sig-expire is used. --no-ask-sig-expire disables this option.
--default-sig-expire
The default expiration time to use for signature expiration. Valid values are "0" for no
expiration, a number followed by the letter d (for days), w (for weeks), m (for months), or y (for
years) (for example "2m" for two months, or "5y" for five years), or an absolute date in the form
YYYY-MM-DD. Defaults to "0".
--ask-cert-expire
--no-ask-cert-expire
When making a key signature, prompt for an expiration time. If this option is not specified, the
expiration time set via --default-cert-expire is used. --no-ask-cert-expire disables this option.
--default-cert-expire
The default expiration time to use for key signature expiration. Valid values are "0" for no
expiration, a number followed by the letter d (for days), w (for weeks), m (for months), or y (for
years) (for example "2m" for two months, or "5y" for five years), or an absolute date in the form
YYYY-MM-DD. Defaults to "0".
--default-new-key-algo string
This option can be used to change the default algorithms for key generation. The string is similar
to the arguments required for the command --quick-add-key but slightly different. You need to
consult the source code to learn the details. Note that the advanced key generation commands can
always be used to specify a key algorithm directly. Setting a compliance mode will set or clear
this flag, so it should only be used after a compliance mode setting.
--no-auto-trust-new-key
When creating a new key the ownertrust of the new key is set to ultimate. This option disables
this and the user needs to manually assign an ownertrust value.
--force-sign-key
This option modifies the behaviour of the commands --quick-sign-key, --quick-lsign-key, and the
"sign" sub-commands of --edit-key by forcing the creation of a key signature, even if one already
exists.
--forbid-gen-key
This option is intended for use in the global config file to disallow the use of generate key
commands. Those commands will then fail with the error code for Not Enabled.
--allow-secret-key-import
This is an obsolete option and is not used anywhere.
--allow-multiple-messages
--no-allow-multiple-messages
These are obsolete options; they have no more effect since GnuPG 2.2.8.
--enable-special-filenames
This option enables a mode in which filenames of the form ‘-&n’, where n is a non-negative decimal
number, refer to the file descriptor n and not to a file with that name.
--no-expensive-trust-checks
Experimental use only.
--preserve-permissions
Don't change the permissions of a secret keyring back to user read/write only. Use this option
only if you really know what you are doing.
--default-preference-list string
Set the list of default preferences to string. This preference list is used for new keys and
becomes the default for "setpref" in the --edit-key menu.
--default-keyserver-url name
Set the default keyserver URL to name. This keyserver will be used as the keyserver URL when
writing a new self-signature on a key, which includes key generation and changing preferences.
--list-config
Display various internal configuration parameters of GnuPG. This option is intended for external
programs that call GnuPG to perform tasks, and is thus not generally useful. See the file
‘doc/DETAILS’ in the source distribution for the details of which configuration items may be
listed. --list-config is only usable with --with-colons set.
--list-gcrypt-config
Display various internal configuration parameters of Libgcrypt.
--gpgconf-list
This command is similar to --list-config but in general only internally used by the gpgconf tool.
--gpgconf-test
This is more or less dummy action. However it parses the configuration file and returns with
failure if the configuration file would prevent gpg from startup. Thus it may be used to run a
syntax check on the configuration file.
--chuid uid
Change the current user to uid which may either be a number or a name. This can be used from the
root account to run gpg for another user. If uid is not the current UID a standard PATH is set
and the envvar GNUPGHOME is unset. To override the latter the option --homedir can be used. This
option has only an effect when used on the command line. This option has currently no effect at
all on Windows.
Deprecated options
-t, --textmode
--no-textmode
Treat input files as text and store them in the OpenPGP canonical text form with standard "CRLF"
line endings. This also sets the necessary flags to inform the recipient that the encrypted or
signed data is text and may need its line endings converted back to whatever the local system
uses. This option was useful when communicating between two platforms with different line ending
conventions (UNIX-like to Mac, Mac to Windows, etc). --no-textmode disables this option, and is
the default. Note that this is a legacy option which should not anymore be used by any modern
software.
--force-v3-sigs
--no-force-v3-sigs
--force-v4-certs
--no-force-v4-certs
These options are obsolete and have no effect since GnuPG 2.1.
--show-photos
--no-show-photos
Causes --list-keys, --list-signatures, --list-public-keys, --list-secret-keys, and verifying a
signature to also display the photo ID attached to the key, if any. See also --photo-viewer. These
options are deprecated. Use --list-options [no-]show-photos and/or --verify-options
[no-]show-photos instead.
--show-keyring
Display the keyring name at the head of key listings to show which keyring a given key resides on.
This option is deprecated: use --list-options [no-]show-keyring instead.
--show-notation
--no-show-notation
Show signature notations in the --list-signatures or --check-signatures listings as well as when
verifying a signature with a notation in it. These options are deprecated. Use --list-options
[no-]show-notation and/or --verify-options [no-]show-notation instead.
--show-policy-url
--no-show-policy-url
Show policy URLs in the --list-signatures or --check-signatures listings as well as when verifying
a signature with a policy URL in it. These options are deprecated. Use --list-options
[no-]show-policy-url and/or --verify-options [no-]show-policy-url instead.
--personal-aead-preferences string
This option is deprecated and has no more effect since version 2.3.9.
--aead-algo name
This option is deprecated and has no more effect since version 2.3.9.
EXAMPLES
gpg -se -r Bob file
sign and encrypt for user Bob
gpg --clear-sign file
make a cleartext signature
gpg -sb file
make a detached signature
gpg -u 0x12345678 -sb file
make a detached signature with the key 0x12345678
gpg --list-keys user_ID
show keys
gpg --fingerprint user_ID
show fingerprint
gpg --verify pgpfile
gpg --verify sigfile [datafile]
Verify the signature of the file but do not output the data unless requested. The second form is
used for detached signatures, where sigfile is the detached signature (either ASCII armored or
binary) and datafile are the signed data; if this is not given, the name of the file holding the
signed data is constructed by cutting off the extension (".asc" or ".sig") of sigfile or by asking
the user for the filename. If the option --output is also used the signed data is written to the
file specified by that option; use - to write the signed data to stdout.
HOW TO SPECIFY A USER ID
There are different ways to specify a user ID to GnuPG. Some of them are only valid for gpg others are
only good for gpgsm. Here is the entire list of ways to specify a key:
By key Id.
This format is deduced from the length of the string and its content or 0x prefix. The key Id of
an X.509 certificate are the low 64 bits of its SHA-1 fingerprint. The use of key Ids is just a
shortcut, for all automated processing the fingerprint should be used.
When using gpg an exclamation mark (!) may be appended to force using the specified primary or
secondary key and not to try and calculate which primary or secondary key to use.
The last four lines of the example give the key ID in their long form as internally used by the
OpenPGP protocol. You can see the long key ID using the option --with-colons.
234567C4
0F34E556E
01347A56A
0xAB123456
234AABBCC34567C4
0F323456784E56EAB
01AB3FED1347A5612
0x234AABBCC34567C4
By fingerprint.
This format is deduced from the length of the string and its content or the 0x prefix. Note, that
only the 20 byte version fingerprint is available with gpgsm (i.e. the SHA-1 hash of the
certificate).
When using gpg an exclamation mark (!) may be appended to force using the specified primary or
secondary key and not to try and calculate which primary or secondary key to use.
The best way to specify a key Id is by using the fingerprint. This avoids any ambiguities in case
that there are duplicated key IDs.
1234343434343434C434343434343434
123434343434343C3434343434343734349A3434
0E12343434343434343434EAB3484343434343434
0xE12343434343434343434EAB3484343434343434
gpgsm also accepts colons between each pair of hexadecimal digits because this is the de-facto standard
on how to present X.509 fingerprints. gpg also allows the use of the space separated SHA-1 fingerprint
as printed by the key listing commands.
By exact match on OpenPGP user ID.
This is denoted by a leading equal sign. It does not make sense for X.509 certificates.
=Heinrich Heine <heinrichh@uni-duesseldorf.de>
By exact match on an email address.
This is indicated by enclosing the email address in the usual way with left and right angles.
<heinrichh@uni-duesseldorf.de>
By partial match on an email address.
This is indicated by prefixing the search string with an @. This uses a substring search but
considers only the mail address (i.e. inside the angle brackets).
@heinrichh
By exact match on the subject's DN.
This is indicated by a leading slash, directly followed by the RFC-2253 encoded DN of the subject.
Note that you can't use the string printed by gpgsm --list-keys because that one has been
reordered and modified for better readability; use --with-colons to print the raw (but standard
escaped) RFC-2253 string.
/CN=Heinrich Heine,O=Poets,L=Paris,C=FR
By exact match on the issuer's DN.
This is indicated by a leading hash mark, directly followed by a slash and then directly followed
by the RFC-2253 encoded DN of the issuer. This should return the Root cert of the issuer. See
note above.
#/CN=Root Cert,O=Poets,L=Paris,C=FR
By exact match on serial number and issuer's DN.
This is indicated by a hash mark, followed by the hexadecimal representation of the serial number,
then followed by a slash and the RFC-2253 encoded DN of the issuer. See note above.
#4F03/CN=Root Cert,O=Poets,L=Paris,C=FR
By keygrip.
This is indicated by an ampersand followed by the 40 hex digits of a keygrip. gpgsm prints the
keygrip when using the command --dump-cert.
&D75F22C3F86E355877348498CDC92BD21010A480
By substring match.
This is the default mode but applications may want to explicitly indicate this by putting the
asterisk in front. Match is not case sensitive.
Heine
*Heine
. and + prefixes
These prefixes are reserved for looking up mails anchored at the end and for a word search mode.
They are not yet implemented and using them is undefined.
Please note that we have reused the hash mark identifier which was used in old GnuPG versions to
indicate the so called local-id. It is not anymore used and there should be no conflict when used
with X.509 stuff.
Using the RFC-2253 format of DNs has the drawback that it is not possible to map them back to the
original encoding, however we don't have to do this because our key database stores this encoding
as meta data.
FILTER EXPRESSIONS
The options --import-filter and --export-filter use expressions with this syntax (square brackets
indicate an optional part and curly braces a repetition, white space between the elements are allowed):
[lc] {[{flag}] PROPNAME op VALUE [lc]}
The name of a property (PROPNAME) may only consist of letters, digits and underscores. The description
for the filter type describes which properties are defined. If an undefined property is used it
evaluates to the empty string. Unless otherwise noted, the VALUE must always be given and may not be the
empty string. No quoting is defined for the value, thus the value may not contain the strings && or ||,
which are used as logical connection operators. The flag -- can be used to remove this restriction.
Numerical values are computed as long int; standard C notation applies. lc is the logical connection
operator; either && for a conjunction or || for a disjunction. A conjunction is assumed at the begin of
an expression. Conjunctions have higher precedence than disjunctions. If VALUE starts with one of the
characters used in any op a space after the op is required.
The supported operators (op) are:
=~ Substring must match.
!~ Substring must not match.
= The full string must match.
<> The full string must not match.
== The numerical value must match.
!= The numerical value must not match.
<= The numerical value of the field must be LE than the value.
< The numerical value of the field must be LT than the value.
> The numerical value of the field must be GT than the value.
>= The numerical value of the field must be GE than the value.
-le The string value of the field must be less or equal than the value.
-lt The string value of the field must be less than the value.
-gt The string value of the field must be greater than the value.
-ge The string value of the field must be greater or equal than the value.
-n True if value is not empty (no value allowed).
-z True if value is empty (no value allowed).
-t Alias for "PROPNAME != 0" (no value allowed).
-f Alias for "PROPNAME == 0" (no value allowed).
Values for flag must be space separated. The supported flags are:
-- VALUE spans to the end of the expression.
-c The string match in this part is done case-sensitive.
-t Leading and trailing spaces are not removed from VALUE. The optional single space after op is
here required.
The filter options concatenate several specifications for a filter of the same type. For example the
four options in this example:
--import-filter keep-uid="uid =~ Alfa"
--import-filter keep-uid="&& uid !~ Test"
--import-filter keep-uid="|| uid =~ Alpha"
--import-filter keep-uid="uid !~ Test"
which is equivalent to
--import-filter \
keep-uid="uid =~ Alfa" && uid !~ Test" || uid =~ Alpha" && "uid !~ Test"
imports only the user ids of a key containing the strings "Alfa" or "Alpha" but not the string "test".
TRUST VALUES
Trust values are used to indicate ownertrust and validity of keys and user IDs. They are displayed with
letters or strings:
-
unknown
No ownertrust assigned / not yet calculated.
e
expired
Trust calculation has failed; probably due to an expired key.
q
undefined, undef
Not enough information for calculation.
n
never Never trust this key.
m
marginal
Marginally trusted.
f
full Fully trusted.
u
ultimate
Ultimately trusted.
r
revoked
For validity only: the key or the user ID has been revoked.
?
err The program encountered an unknown trust value.
FILES
There are a few configuration files to control certain aspects of gpg's operation. Unless noted, they are
expected in the current home directory (see: [option --homedir]).
gpg.conf
This is the standard configuration file read by gpg on startup. It may contain any valid long
option; the leading two dashes may not be entered and the option may not be abbreviated. This
default name may be changed on the command line (see: [gpg-option --options]). You should backup
this file.
common.conf
This is an optional configuration file read by gpg on startup. It may contain options pertaining
to all components of GnuPG. Its current main use is for the "use-keyboxd" option. If the default
home directory ‘~/.gnupg’ does not exist, GnuPG creates this directory and a ‘common.conf’ file
with "use-keyboxd".
Note that on larger installations, it is useful to put predefined files into the directory
‘/etc/skel/.gnupg’ so that newly created users start up with a working configuration. For existing users
a small helper script is provided to create these files (see: [addgnupghome]).
For internal purposes gpg creates and maintains a few other files; They all live in the current home
directory (see: [option --homedir]). Only the gpg program may modify these files.
~/.gnupg
This is the default home directory which is used if neither the environment variable GNUPGHOME nor
the option --homedir is given.
~/.gnupg/pubring.gpg
The public keyring using a legacy format. You should backup this file.
If this file is not available, gpg defaults to the new keybox format and creates a file
‘pubring.kbx’ unless that file already exists in which case that file will also be used for
OpenPGP keys.
Note that in the case that both files, ‘pubring.gpg’ and ‘pubring.kbx’ exists but the latter has
no OpenPGP keys, the legacy file ‘pubring.gpg’ will be used. Take care: GnuPG versions before 2.1
will always use the file ‘pubring.gpg’ because they do not know about the new keybox format. In
the case that you have to use GnuPG 1.4 to decrypt archived data you should keep this file.
~/.gnupg/pubring.gpg.lock
The lock file for the public keyring.
~/.gnupg/pubring.kbx
The public keyring using the new keybox format. This file is shared with gpgsm. You should
backup this file. See above for the relation between this file and it predecessor.
To convert an existing ‘pubring.gpg’ file to the keybox format, you first backup the ownertrust
values, then rename ‘pubring.gpg’ to ‘publickeys.backup’, so it won’t be recognized by any GnuPG
version, run import, and finally restore the ownertrust values:
$ cd ~/.gnupg
$ gpg --export-ownertrust >otrust.lst
$ mv pubring.gpg publickeys.backup
$ gpg --import-options restore --import publickeys.backup
$ gpg --import-ownertrust otrust.lst
~/.gnupg/pubring.kbx.lock
The lock file for ‘pubring.kbx’.
~/.gnupg/secring.gpg
The legacy secret keyring as used by GnuPG versions before 2.1. It is not used by GnuPG 2.1 and
later. You may want to keep it in case you have to use GnuPG 1.4 to decrypt archived data.
~/.gnupg/secring.gpg.lock
The lock file for the legacy secret keyring.
~/.gnupg/.gpg-v21-migrated
File indicating that a migration to GnuPG 2.1 has been done.
~/.gnupg/trustdb.gpg
The trust database. There is no need to backup this file; it is better to backup the ownertrust
values (see: [option --export-ownertrust]).
~/.gnupg/trustdb.gpg.lock
The lock file for the trust database.
~/.gnupg/random_seed
A file used to preserve the state of the internal random pool.
~/.gnupg/openpgp-revocs.d/
This is the directory where gpg stores pre-generated revocation certificates. The file name
corresponds to the OpenPGP fingerprint of the respective key. It is suggested to backup those
certificates and if the primary private key is not stored on the disk to move them to an external
storage device. Anyone who can access these files is able to revoke the corresponding key. You
may want to print them out. You should backup all files in this directory and take care to keep
this backup closed away.
Operation is further controlled by a few environment variables:
HOME Used to locate the default home directory.
GNUPGHOME
If set directory used instead of "~/.gnupg".
GPG_AGENT_INFO
This variable is obsolete; it was used by GnuPG versions before 2.1.
PINENTRY_USER_DATA
This value is passed via gpg-agent to pinentry. It is useful to convey extra information to a
custom pinentry.
COLUMNS
LINES Used to size some displays to the full size of the screen.
LANGUAGE
Apart from its use by GNU, it is used in the W32 version to override the language selection done
through the Registry. If used and set to a valid and available language name (langid), the file
with the translation is loaded from gpgdir/gnupg.nls/langid.mo. Here gpgdir is the directory out
of which the gpg binary has been loaded. If it can't be loaded the Registry is tried and as last
resort the native Windows locale system is used.
GNUPG_BUILD_ROOT
This variable is only used by the regression test suite as a helper under operating systems
without proper support to figure out the name of a process' text file.
GNUPG_EXEC_DEBUG_FLAGS
This variable allows one to enable diagnostics for process management. A numeric decimal value is
expected. Bit 0 enables general diagnostics, bit 1 enables certain warnings on Windows.
When calling the gpg-agent component gpg sends a set of environment variables to gpg-agent. The names of
these variables can be listed using the command:
gpg-connect-agent 'getinfo std_env_names' /bye | awk '$1=="D" {print $2}'
NOTES
gpg is often used as a backend engine by other software. To help with this a machine interface has been
defined to have an unambiguous way to do this. The options --status-fd and --batch are almost always
required for this.
Programmatic use of GnuPG
Please consider using GPGME instead of calling gpg directly. GPGME offers a stable, backend-independent
interface for many cryptographic operations. It supports OpenPGP and S/MIME, and also allows interaction
with various GnuPG components.
GPGME provides a C-API, and comes with bindings for C++, Qt, and Python. Bindings for other languages
are available.
Ephemeral home directories
Sometimes you want to contain effects of some operation, for example you want to import a key to inspect
it, but you do not want this key to be added to your keyring. In earlier versions of GnuPG, it was
possible to specify alternate keyring files for both public and secret keys. In modern GnuPG versions,
however, we changed how secret keys are stored in order to better protect secret key material, and it was
not possible to preserve this interface.
The preferred way to do this is to use ephemeral home directories. This technique works across all
versions of GnuPG.
Create a temporary directory, create (or copy) a configuration that meets your needs, make gpg use this
directory either using the environment variable GNUPGHOME, or the option --homedir. GPGME supports this
too on a per-context basis, by modifying the engine info of contexts. Now execute whatever operation you
like, import and export key material as necessary. Once finished, you can delete the directory. All
GnuPG backend services that were started will detect this and shut down.
The quick key manipulation interface
Recent versions of GnuPG have an interface to manipulate keys without using the interactive command
--edit-key. This interface was added mainly for the benefit of GPGME (please consider using GPGME, see
the manual subsection ``Programmatic use of GnuPG''). This interface is described in the subsection
``How to manage your keys''.
Unattended key generation
The command --generate-key may be used along with the option --batch for unattended key generation. This
is the most flexible way of generating keys, but it is also the most complex one. Consider using the
quick key manipulation interface described in the previous subsection ``The quick key manipulation
interface''.
The parameters for the key are either read from stdin or given as a file on the command line. The format
of the parameter file is as follows: Text only, line length is limited to about 1000 characters. UTF-8
encoding must be used to specify non-ASCII characters. Empty lines are ignored. Leading and trailing
white space is ignored. A hash sign as the first non white space character indicates a comment line.
Control statements are indicated by a leading percent sign, their arguments are separated by white space
from the keyword. Parameters are specified by a keyword, followed by a colon; arguments are separated by
white space. The first parameter must be ‘Key-Type’ but control statements may be placed anywhere. The
order of the parameters does not matter except for ‘Key-Type’. The parameters are only used for the
generated keyblock (primary and subkeys); parameters from previous sets are not used. Some syntax checks
may be performed. Key commences when either the end of the parameter file is reached, the next
‘Key-Type’ parameter is encountered, or the control statement ‘%commit’ is encountered.
Control statements:
%echo text
Print text as diagnostic.
%dry-run
Suppress actual key generation (useful for syntax checking).
%commit
Perform the key generation. Note that an implicit commit is done at the next parameter.
%pubring filename
Do not write the key to the default or commandline given keyring but to filename. This must be
given before the first commit to take place, duplicate specification of the same filename is
ignored, the last filename before a commit is used. The filename is used until a new filename is
used (at commit points) and all keys are written to that file. If a new filename is given, this
file is created (and overwrites an existing one).
See the previous subsection ``Ephemeral home directories'' for a more robust way to contain side-
effects.
%secring filename
This option is a no-op for GnuPG 2.1 and later.
See the previous subsection ``Ephemeral home directories''.
%ask-passphrase
%no-ask-passphrase
This option is a no-op since GnuPG version 2.1.
%no-protection
Using this option allows the creation of keys without any passphrase protection. This option is
mainly intended for regression tests.
%transient-key
If given the keys are created using a faster and a somewhat less secure random number generator.
This option may be used for keys which are only used for a short time and do not require full
cryptographic strength. It takes only effect if used together with the control statement
‘%no-protection’.
General Parameters:
Key-Type: algo
Starts a new parameter block by giving the type of the primary key. The algorithm must be capable
of signing. This is a required parameter. algo may either be an OpenPGP algorithm number or a
string with the algorithm name. The special value ‘default’ may be used for algo to create the
default key type; in this case a ‘Key-Usage’ shall not be given and ‘default’ also be used for
‘Subkey-Type’.
Key-Length: nbits
The requested length of the generated key in bits. The default is returned by running the command
‘gpg --gpgconf-list’. For ECC keys this parameter is ignored.
Key-Curve: curve
The requested elliptic curve of the generated key. This is a required parameter for ECC keys. It
is ignored for non-ECC keys.
Key-Grip: hexstring
This is optional and used to generate a CSR or certificate for an already existing key. Key-
Length will be ignored when given.
Key-Usage: usage-list
Space or comma delimited list of key usages. Allowed values are ‘encrypt’, ‘sign’, and ‘auth’.
This is used to generate the key flags. Please make sure that the algorithm is capable of this
usage. Note that OpenPGP requires that all primary keys are capable of certification, so no
matter what usage is given here, the ‘cert’ flag will be on. If no ‘Key-Usage’ is specified and
the ‘Key-Type’ is not ‘default’, all allowed usages for that particular algorithm are used; if it
is not given but ‘default’ is used the usage will be ‘sign’.
Subkey-Type: algo
This generates a secondary key (subkey). Currently only one subkey can be handled. See also
‘Key-Type’ above.
Subkey-Length: nbits
Length of the secondary key (subkey) in bits. The default is returned by running the command ‘gpg
--gpgconf-list’.
Subkey-Curve: curve
Key curve for a subkey; similar to ‘Key-Curve’.
Subkey-Usage: usage-list
Key usage lists for a subkey; similar to ‘Key-Usage’.
Passphrase: string
If you want to specify a passphrase for the secret key, enter it here. Default is to use the
Pinentry dialog to ask for a passphrase.
Name-Real: name
Name-Comment: comment
Name-Email: email
The three parts of a user name. Remember to use UTF-8 encoding here. If you don't give any of
them, no user ID is created.
Expire-Date: iso-date|(number[d|w|m|y])
Set the expiration date for the key (and the subkey). It may either be entered in ISO date format
(e.g. "20000815T145012") or as number of days, weeks, month or years after the creation date. The
special notation "seconds=N" is also allowed to specify a number of seconds since creation.
Without a letter days are assumed. Note that there is no check done on the overflow of the type
used by OpenPGP for timestamps. Thus you better make sure that the given value make sense.
Although OpenPGP works with time intervals, GnuPG uses an absolute value internally and thus the
last year we can represent is 2105.
Creation-Date: iso-date
Set the creation date of the key as stored in the key information and which is also part of the
fingerprint calculation. Either a date like "1986-04-26" or a full timestamp like
"19860426T042640" may be used. The time is considered to be UTC. The special notation
"seconds=N" may be used to directly specify a the number of seconds since Epoch (Unix time). If
it is not given the current time is used.
Preferences: string
Set the cipher, hash, and compression preference values for this key. This expects the same type
of string as the sub-command ‘setpref’ in the --edit-key menu.
Revoker: algo:fpr [sensitive]
Add a designated revoker to the generated key. Algo is the public key algorithm of the designated
revoker (i.e. RSA=1, DSA=17, etc.) fpr is the fingerprint of the designated revoker. fpr may not
contain spaces or colons. The optional ‘sensitive’ flag marks the designated revoker as sensitive
information. Only v4 and v5 keys may be designated revokers.
Keyserver: string
This is an optional parameter that specifies the preferred keyserver URL for the key.
Handle: string
This is an optional parameter only used with the status lines KEY_CREATED and KEY_NOT_CREATED.
string may be up to 100 characters and should not contain spaces. It is useful for batch key
generation to associate a key parameter block with a status line.
Here is an example on how to create a key in an ephemeral home directory:
$ export GNUPGHOME="$(mktemp -d)"
$ cat >foo <<EOF
%echo Generating a basic OpenPGP key
Key-Type: DSA
Key-Length: 1024
Subkey-Type: ELG-E
Subkey-Length: 1024
Name-Real: Joe Tester
Name-Comment: with stupid passphrase
Name-Email: joe@foo.bar
Expire-Date: 0
Passphrase: abc
# Do a commit here, so that we can later print "done" :-)
%commit
%echo done
EOF
$ gpg --batch --generate-key foo
[...]
$ gpg --list-secret-keys
/tmp/tmp.0NQxB74PEf/pubring.kbx
-------------------------------
sec dsa1024 2016-12-16 [SCA]
768E895903FC1C44045C8CB95EEBDB71E9E849D0
uid [ultimate] Joe Tester (with stupid passphrase) <joe@foo.bar>
ssb elg1024 2016-12-16 [E]
If you want to create a key with the default algorithms you would use these parameters:
%echo Generating a default key
Key-Type: default
Subkey-Type: default
Name-Real: Joe Tester
Name-Comment: with stupid passphrase
Name-Email: joe@foo.bar
Expire-Date: 0
Passphrase: abc
# Do a commit here, so that we can later print "done" :-)
%commit
%echo done
BUGS
On older systems this program should be installed as setuid(root). This is necessary to lock memory
pages. Locking memory pages prevents the operating system from writing memory pages (which may contain
passphrases or other sensitive material) to disk. If you get no warning message about insecure memory
your operating system supports locking without being root. The program drops root privileges as soon as
locked memory is allocated.
Note also that some systems (especially laptops) have the ability to ``suspend to disk'' (also known as
``safe sleep'' or ``hibernate''). This writes all memory to disk before going into a low power or even
powered off mode. Unless measures are taken in the operating system to protect the saved memory,
passphrases or other sensitive material may be recoverable from it later.
Before you report a bug you should first search the mailing list archives for similar problems and second
check whether such a bug has already been reported to our bug tracker at https://bugs.gnupg.org.
SEE ALSO
gpgv(1), gpgsm(1), gpg-agent(1)
The full documentation for this tool is maintained as a Texinfo manual. If GnuPG and the info program
are properly installed at your site, the command
info gnupg
should give you access to the complete manual including a menu structure and an index.
GnuPG 2.4.7 2024-11-22 GPG(1)