Ubuntu Manpage: ASN1_generate_nconf, ASN1_generate_v3

Provided by: libssl-doc_3.0.13-0ubuntu3.5_all

NAME

       ASN1_generate_nconf, ASN1_generate_v3 - ASN1 string generation functions

SYNOPSIS

        #include <openssl/asn1.h>

        ASN1_TYPE *ASN1_generate_nconf(const char *str, CONF *nconf);
        ASN1_TYPE *ASN1_generate_v3(const char *str, X509V3_CTX *cnf);

DESCRIPTION

       These functions generate the ASN1 encoding of a string in an ASN1_TYPE structure.

       str contains the string to encode. nconf or cnf contains the optional configuration information where
       additional strings will be read from. nconf will typically come from a config file whereas cnf is
       obtained from an X509V3_CTX structure, which will typically be used by X509 v3 certificate extension
       functions. cnf or nconf can be set to NULL if no additional configuration will be used.

GENERATION STRING FORMAT

The actual data encoded is determined by the string str and the configuration information. The general
format of the string is:

[modifier,]type[:value]

That is zero or more comma separated modifiers followed by a type followed by an optional colon and a
value. The formats of type, value and modifier are explained below.

Supported Types
The supported types are listed below. Case is not significant in the type names. Unless otherwise
specified only the ASCII format is permissible.

BOOLEAN, BOOL
This encodes a boolean type. The value string is mandatory and should be TRUE or FALSE. Additionally
TRUE, true, Y, y, YES, yes, FALSE, false, N, n, NO and no are acceptable.

NULL
Encode the NULL type, the value string must not be present.

INTEGER, INT
Encodes an ASN1 INTEGER type. The value string represents the value of the integer, it can be
prefaced by a minus sign and is normally interpreted as a decimal value unless the prefix 0x is
included.

ENUMERATED, ENUM
Encodes the ASN1 ENUMERATED type, it is otherwise identical to INTEGER.

OBJECT, OID
Encodes an ASN1 OBJECT IDENTIFIER, the value string can be a short name, a long name or numerical
format.

UTCTIME, UTC
Encodes an ASN1 UTCTime structure, the value should be in the format YYMMDDHHMMSSZ.

GENERALIZEDTIME, GENTIME
Encodes an ASN1 GeneralizedTime structure, the value should be in the format YYYYMMDDHHMMSSZ.

OCTETSTRING, OCT
Encodes an ASN1 OCTET STRING. value represents the contents of this structure, the format strings
ASCII and HEX can be used to specify the format of value.

BITSTRING, BITSTR
Encodes an ASN1 BIT STRING. value represents the contents of this structure, the format strings
ASCII, HEX and BITLIST can be used to specify the format of value.

If the format is anything other than BITLIST the number of unused bits is set to zero.

UNIVERSALSTRING, UNIV, IA5, IA5STRING, UTF8, UTF8String, BMP, BMPSTRING, VISIBLESTRING, VISIBLE,
PRINTABLESTRING, PRINTABLE, T61, T61STRING, TELETEXSTRING, GeneralString, NUMERICSTRING, NUMERIC
These encode the corresponding string types. value represents the contents of this structure. The
format can be ASCII or UTF8.

SEQUENCE, SEQ, SET
Formats the result as an ASN1 SEQUENCE or SET type. value should be a section name which will contain
the contents. The field names in the section are ignored and the values are in the generated string
format. If value is absent then an empty SEQUENCE will be encoded.

Modifiers
Modifiers affect the following structure, they can be used to add EXPLICIT or IMPLICIT tagging, add
wrappers or to change the string format of the final type and value. The supported formats are documented
below.

EXPLICIT, EXP
Add an explicit tag to the following structure. This string should be followed by a colon and the tag
value to use as a decimal value.

By following the number with U, A, P or C UNIVERSAL, APPLICATION, PRIVATE or CONTEXT SPECIFIC tagging
can be used, the default is CONTEXT SPECIFIC.

IMPLICIT, IMP
This is the same as EXPLICIT except IMPLICIT tagging is used instead.

OCTWRAP, SEQWRAP, SETWRAP, BITWRAP
The following structure is surrounded by an OCTET STRING, a SEQUENCE, a SET or a BIT STRING
respectively. For a BIT STRING the number of unused bits is set to zero.

FORMAT
This specifies the format of the ultimate value. It should be followed by a colon and one of the
strings ASCII, UTF8, HEX or BITLIST.

If no format specifier is included then ASCII is used. If UTF8 is specified then the value string
must be a valid UTF8 string. For HEX the output must be a set of hex digits. BITLIST (which is only
valid for a BIT STRING) is a comma separated list of the indices of the set bits, all other bits are
zero.

RETURN VALUES

       ASN1_generate_nconf() and ASN1_generate_v3() return the encoded data as an ASN1_TYPE structure or NULL if
       an error occurred.

       The error codes that can be obtained by ERR_get_error(3).

EXAMPLES

       A simple IA5String:

        IA5STRING:Hello World

       An IA5String explicitly tagged:

        EXPLICIT:0,IA5STRING:Hello World

       An IA5String explicitly tagged using APPLICATION tagging:

        EXPLICIT:0A,IA5STRING:Hello World

       A BITSTRING with bits 1 and 5 set and all others zero:

        FORMAT:BITLIST,BITSTRING:1,5

       A  more  complex  example  using  a  config  file to produce a SEQUENCE consisting of a BOOL an OID and a
       UTF8String:

        asn1 = SEQUENCE:seq_section

        [seq_section]

        field1 = BOOLEAN:TRUE
        field2 = OID:commonName
        field3 = UTF8:Third field

       This example produces an RSAPrivateKey structure, this is the key contained in the file client.pem in all
       OpenSSL distributions (note: the field names such as  'coeff'  are  ignored  and  are  present  just  for
       clarity):

        asn1=SEQUENCE:private_key
        [private_key]
        version=INTEGER:0

        n=INTEGER:0xBB6FE79432CC6EA2D8F970675A5A87BFBE1AFF0BE63E879F2AFFB93644\
        D4D2C6D000430DEC66ABF47829E74B8C5108623A1C0EE8BE217B3AD8D36D5EB4FCA1D9

        e=INTEGER:0x010001

        d=INTEGER:0x6F05EAD2F27FFAEC84BEC360C4B928FD5F3A9865D0FCAAD291E2A52F4A\
        F810DC6373278C006A0ABBA27DC8C63BF97F7E666E27C5284D7D3B1FFFE16B7A87B51D

        p=INTEGER:0xF3929B9435608F8A22C208D86795271D54EBDFB09DDEF539AB083DA912\
        D4BD57

        q=INTEGER:0xC50016F89DFF2561347ED1186A46E150E28BF2D0F539A1594BBD7FE467\
        46EC4F

        exp1=INTEGER:0x9E7D4326C924AFC1DEA40B45650134966D6F9DFA3A7F9D698CD4ABEA\
        9C0A39B9

        exp2=INTEGER:0xBA84003BB95355AFB7C50DF140C60513D0BA51D637272E355E397779\
        E7B2458F

        coeff=INTEGER:0x30B9E4F2AFA5AC679F920FC83F1F2DF1BAF1779CF989447FABC2F5\
        628657053A

       This example is the corresponding public key in a SubjectPublicKeyInfo structure:

        # Start with a SEQUENCE
        asn1=SEQUENCE:pubkeyinfo

        # pubkeyinfo contains an algorithm identifier and the public key wrapped
        # in a BIT STRING
        [pubkeyinfo]
        algorithm=SEQUENCE:rsa_alg
        pubkey=BITWRAP,SEQUENCE:rsapubkey

        # algorithm ID for RSA is just an OID and a NULL
        [rsa_alg]
        algorithm=OID:rsaEncryption
        parameter=NULL

        # Actual public key: modulus and exponent
        [rsapubkey]
        n=INTEGER:0xBB6FE79432CC6EA2D8F970675A5A87BFBE1AFF0BE63E879F2AFFB93644\
        D4D2C6D000430DEC66ABF47829E74B8C5108623A1C0EE8BE217B3AD8D36D5EB4FCA1D9

        e=INTEGER:0x010001

COPYRIGHT

       Copyright 2002-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed  under  the  Apache License 2.0 (the "License").  You may not use this file except in compliance
       with the License.  You can obtain  a  copy  in  the  file  LICENSE  in  the  source  distribution  or  at
       <https://www.openssl.org/source/license.html>.

3.0.13                                             2025-02-05                          ASN1_GENERATE_NCONF(3SSL)