.\" Hey, Emacs!  This is an -*- nroff -*- source file.
.TH GOST12SUM 1 "02 Aug 2016" "Openssl" "Debian GNU/Linux"
.SH NAME
gost12sum \- generates or checks GOST R34.11-2012 message digests

.SH SYNOPSIS
.B gost12sum
[\-bvl] [\-c [file]] | [file...]

.SH DESCRIPTION
.B gost12sum
generates or checks GOST hash sums. The algorithm to generate the
is reasonably fast and strong enough for most cases. Exact
specification of the algorithm is in
.I GOST R34.11-2012.

Normally
.B gost12sum
generates checksums of all files given to it as a parameter and prints
the checksums followed by the filenames. If, however,
.B \-c
is specified, only one filename parameter is allowed. This file should
contain checksums and filenames to which these checksums refer to, and
the files listed in that file are checked against the checksums listed
there. See option
.B \-c
for more information.

.SS OPTIONS
.TP
.B \-b
Use binary mode. In unix environment, only difference between this and
the normal mode is an asterisk preceding the filename in the output.
.TP
.B \-c
Check gost hashes of all files listed in
.I file
against the checksum listed in the same file. The actual format of that
file is the same as output of
.B md5sum.
That is, each line in the file describes a file. A line looks like:

.B <hashsum>  <filename>

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

.B echo foo > hash\-test\-file; gost12sum hash\-test\-file

.B gost12sum
would report:

3d4a51ee7713e6467442facefe06f153a303e7bdefbe7f9bdf2edb4ae9c866ff hash\-test\-file

When invoked with \-c option
.B gost12sum 
normally works silently unless error found. Use \-v if you want to see
list of successfully checked files

.TP
.B \-v
Be more verbose. Print filenames when checking (with \-c).

.TP
.B -l 
Use long (512-bit) hash instead of short (256-bit).

.SH BUGS

This manpage is not quite accurate and has formatting inconsistent
with other manpages.

.B gost12sum
does not accept standard options like
.BR \-\-help .

.SH AUTHOR

.B gost12sum
utility written by Cryptocom LTD

This manual page is written by Victor Wagner <vitus@wagner.pp.ru> for
Debian GNU/Linux