NAME
cookfp - calculate file fingerprint
SYNOPSIS
cookfp [ option... ][ filename... ]
cookfp -Help
cookfp -VERSion
DESCRIPTION
The cookfp program is used to calculate the fingerprints of files. A
fingerprint is a hash of the contents of a file. The default
fingerprint is cryptographically strong, so the probability of two
different files having the same fingerprint is less than 1 in 2**200.
The fingerprint is based on Dan Berstien <djb@silverton.berkeley.edu>
public domain fingerprint 0.50 beta package 930809, posted to the
alt.sources newsgroup. This program produces identical results; the
expected test results were generated using Dan’s package.
The fingerprint is a base-64-sanely-encoded fingerprint of the input.
Imagine this fingerprint as something universal and permanent. A
fingerprint is 76 characters long, containing the following:
1. A Snefru-8 (version 2.5, 8 passes, 512->256) hash. (Derived from
the Xerox Secure Hash Function.)
2. An MD5 hash, as per RFC 1321. (Derived from the RSADSI MD5
Message-Digest Algorithm.)
3. A CRC checksum, as in the new cksum utility.
4. Length modulo 2^40.
The output format is not expected to be compatible with anything.
However, options are available to produce the purported output of
Merkle’s snefru program, the purported output of RSADSI’s mddriver -x,
or the purported output of the POSIX cksum program.
If no files are named as input, the standard input will be used. The
special file name ‘‘-’’ is understood to mean the standard input.
OPTIONS
The following options are understood:
-Checksum
Print the CRC32 checksum and length of the named file(s).
-Identifier
Print a condensed form of the fingerprint (obtained by
performing a CRC32 checksum on the full fingerprint described
above - a definite overkill). This is an 8-digit hexadecimal
number, useful for generating unique short identifiers out of
long names. The first character is forced to be a letter (g-
p), so there is no problem in using the output as a variable
name.
-Help
Provide some help with using the cookfp program.
-Message_Digest
Print the RSA Data Security, Inc. MD5 Message-Digest Algorithm
hash of the named file(s).
-Snefru Print the Snefru hash of the named file(s), derived from the
Xerox Secure Hash Function.
-VERSion
Print the version of the cookfp program being executed.
All other options will produce a diagnostic error.
All options may be abbreviated; the abbreviation is documented as the
upper case letters, all lower case letters and underscores (_) are
optional. You must use consecutive sequences of optional letters.
All options are case insensitive, you may type them in upper case or
lower case or a combination of both, case is not important.
For example: the arguments "-help", "-HEL" and "-h" are all interpreted
to mean the -Help option. The argument "-hlp" will not be understood,
because consecutive optional characters were not supplied.
Options and other command line arguments may be mixed arbitrarily on
the command line.
The GNU long option names are understood. Since all option names for
cookfp are long, this means ignoring the extra leading ’-’. The
"--option=value" convention is also understood.
EXIT STATUS
The cookfp command will exit with a status of 1 on any error. The
cookfp command will only exit with a status of 0 if there are no
errors.
COPYRIGHT
cookfp version 2.33
Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
2009 Peter Miller
The cookfp program comes with ABSOLUTELY NO WARRANTY; for details use
the ’cookfp -VERSion License’ command. This is free software and you
are welcome to redistribute it under certain conditions; for details
use the ’cookfp -VERSion License’ command.
AUTHOR
Peter Miller E-Mail: pmiller@opensource.org.au
/\/\* WWW: http://miller.emu.id.au/pmiller/
Portions of this program are derived from sources from other people,
sometimes with liberal copyrights, and sometimes in the public domain.
These include:
Dan Bernstien
See common/fp/README for details.
Gary S Brown.
See common/fp/crc32.c for details.
RSA Data Security, Inc.
See common/fp/md5.c for details.
Xerox Corporation
See common/fp/snefru.c for details.
In addition to the above copyright holders, there have been numerous
authors and contributors, see the named files for details. Files names
are relative to the root of the cook distribution.