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MD5(1)                  FreeBSD General Commands Manual                 MD5(1)

NAME
     md5, sha1, sha256, rmd160 -- calculate a message-digest fingerprint
     (checksum) for a file

SYNOPSIS
     md5 [-pqrtx] [-s string] [file ...]
     sha1 [-pqrtx] [-s string] [file ...]
     sha256 [-pqrtx] [-s string] [file ...]
     rmd160 [-pqrtx] [-s string] [file ...]

DESCRIPTION
     The md5, sha1, sha256 and rmd160 utilities take as input a message of
     arbitrary length and produce as output a ``fingerprint'' or ``message
     digest'' of the input.  It is conjectured that it is computationally
     infeasible to produce two messages having the same message digest, or to
     produce any message having a given prespecified target message digest.
     The MD5, SHA-1, SHA-256 and RIPEMD-160 algorithms are intended for digi-
     tal signature applications, where a large file must be ``compressed'' in
     a secure manner before being encrypted with a private (secret) key under
     a public-key cryptosystem such as RSA.

     MD5 has not yet (2001-09-03) been broken, but sufficient attacks have
     been made that its security is in some doubt.  The attacks on MD5 are in
     the nature of finding ``collisions'' -- that is, multiple inputs which
     hash to the same value; it is still unlikely for an attacker to be able
     to determine the exact original input given a hash value.

     The following options may be used in any combination and must precede any
     files named on the command line.  The hexadecimal checksum of each file
     listed on the command line is printed after the options are processed.

     -s string
             Print a checksum of the given string.

     -p      Echo stdin to stdout and append the checksum to stdout.

     -q      Quiet mode - only the checksum is printed out.  Overrides the -r
             option.

     -r      Reverses the format of the output.  This helps with visual diffs.
             Does nothing when combined with the -ptx options.

     -t      Run a built-in time trial.

     -x      Run a built-in test script.

EXIT STATUS
     The md5, sha1, sha256 and rmd160 utilities exit 0 on success, and 1 if at
     least one of the input files could not be read.

SEE ALSO
     cksum(1), md5(3), ripemd(3), sha(3), sha256(3)

     R. Rivest, The MD5 Message-Digest Algorithm, RFC1321.

     J. Burrows, The Secure Hash Standard, FIPS PUB 180-2.

     D. Eastlake and P. Jones, US Secure Hash Algorithm 1, RFC 3174.

     RIPEMD-160 is part of the ISO draft standard "ISO/IEC DIS 10118-3" on
     dedicated hash functions.

     Secure Hash Standard (SHS): http://csrc.nist.gov/cryptval/shs.html.

     The RIPEMD-160 page:
     http://www.esat.kuleuven.ac.be/~bosselae/ripemd160.html.

ACKNOWLEDGMENTS
     This program is placed in the public domain for free general use by RSA
     Data Security.

     Support for SHA-1 and RIPEMD-160 has been added by Oliver Eikemeier
     <eik@FreeBSD.org>.

FreeBSD 6.2                      June 6, 2004                      FreeBSD 6.2

NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | SEE ALSO | ACKNOWLEDGMENTS

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