Ubuntu Manpage: tthsum ‐ generates or checks TTH message digests

NAME

       tthsum ‐ generates or checks TTH message digests

SYNOPSIS

       tthsum [-bhmpvVw] [-c [file]] | [file...]

DESCRIPTION

tthsum generates or checks TTH checksums (roots of the Tiger/THEX hash tree). The Merkle Hash Tree,
invented by Ralph Merkle, is a hash construct that exhibits desirable properties for verifying the
integrity of files and file subranges in an incremental or out‐of‐order fashion. tthsum uses the Tiger
hash algorithm, by Ross Anderson and Eli Biham, for both the internal and the leaf nodes.

The specification of the THEX algorithm is at:
. http://tthsum.devs.nu/draft-jchapweske-thex-02.html

The specification of the Tiger hash algorithm is at:
. http://www.cs.technion.ac.il/~biham/Reports/Tiger/

Normally tthsum generates checksums of all files given to it as parameters and prints the checksums
followed by the filenames. If, however, -c is specified, only one filename parameter is allowed. This
file should contain checksums and filenames to which these checksums refer, and the files listed in that
file are checked against the checksums listed there. See option -c for more information.

If no file is specified data will be read from standard input.

OPTIONS
-b An md5sum compatibility option. It does absolutely nothing. (md5sum uses -b to treat binary files
differently from texts files.)

-c Check tthsum of all files listed in file against the checksum listed in the same file. The actual
format of that file is the same as output of tthsum. That is, each line in the file describes a
file. A line looks like:

So, for example, if a file were created and its message digest calculated like so:

echo foo > tth-test-file; tthsum tth-test-file

tthsum would report:

A2MPPCGS5CPJV6AOAP37ICDCFV3WYU7PBREC6FY tth-test-file

See NOTES for more information on the digest file format.

-m Use mmap(2) instead of read(2) to read the contents of the files to hash. Normally, using read is
cheaper. This all depends on system load, I/O speed, CPU speed, L1 and/or L2 cache size and
whatnot.

-p Show the progress. Print the percentage of completeness while hashing on standard error. Prints
file position instead of percentage when the file size is unknown.

-v Be verbose. Print filenames when checking (with -c).

-w Warn on improperly formatted lines when checking (with -c).

-h, -V Print a small help text or the version, respectively, on standard out. If an unknown combination
of options is encountered, the small help is printed on standard error and tthsum will return non‐
zero.

RETURN VALUE

       tthsum  returns  0  if  no  error  occurred or, when checking a digest, if at least one line is formatted
       properly and the TTHs of all properly formatted lines match.  tthsum returns 2 if an unknown  combination
       of options is encountered.  In all other cases will tthsum return 1.

NOTES

       tthsum intentionally uses an interface identical to md5sum.

       tthsum uses BASE32 encoding consisting of the following characters: ABCDEFGHIJKLMNOPQRSTUVWXYZ234567.  It
       will accept lower case letters in the digest input as well.

       tthsum does not accept long options such as --help.

       A  digest  file  format  line looks like: <BASE32><SPACES><FILENAME><EOL>.  BASE32 is a 39 character long
       BASE32 encoded string.  SPACES is a set of two spaces (0x20).  FILENAME is the name of the file,  encoded
       in  UTF8  and  with all control characters (those below 0x20) encoded as \xNN or \C C‐style escapes. (The
       backslash is escaped as \\ as well. On Windows, backslashes in paths will be translated  to  slashes  for
       compatibility  with  real operating systems.)  EOL may be CRLF (\r\n), just plain LF (\n) or even nothing
       at end‐of‐file.

       If you see warnings about  an  improper  locale  setup,  check  your  LANG  and/or  LC_CTYPE  environment
       variables.   If  these  are  not  set properly, tthsum cannot represent non‐ASCII characters (those above
       0x7F) in UTF8. See locale(1) for more information or try to set LC_CTYPE to e.g. "en_US".

REPORTING BUGS

       Report bugs to <walter+tthsum@wjd.nu>.

COPYRIGHT

       Copyright   ©   2009   Walter   Doekes.    License   GPLv3+:    GNU    GPL    version    3    or    later
       <http://gnu.org/licenses/gpl.html>
       This  is  free software: you are free to change and redistribute it.  There is NO WARRANTY, to the extent
       permitted by law.

AUTHOR

       tthsum and this manpage were written by Walter  Doekes  (walter+tthsum@wjd.nu).   The  hashing  code  was
       copied   directly   from  DC++,  an  open  source  peer‐to‐peer  file  sharing  program  by  Jacek  Sieka
       (jacek@creatio.se) who had based the hashing code on the one used in BCDC++ (a modified DC++)  by  Dustin
       Brody (blackclaw@parsoma.net).  After version 1.1.0, the hashing code from the Tiger hash authors is used
       instead, to support big endian architectures and to remove the need for C++ compilers and libraries.  The
       md5sum  manpage, written by Juho Vuori (javuori@cc.helsinki.fi), was used as a template. This manpage was
       proofread by Dustin Brody.