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MD5(1)				   BSD 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 digital signature applica-
     tions, 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 been completely broken as far as finding collisions is concerned, and should not be
     relied upon to produce unique outputs.  This also means that MD5 should not be used as part
     of a cryptographic signature scheme.  At the current time (2009-01-06) there is no publicly
     known method to ``reverse'' MD5, i.e., to find an input given a hash value.

     SHA-1 currently (2009-01-06) has no known collisions, but an attack has been found which is
     faster than a brute-force search, placing the security of SHA-1 in doubt.

     It is recommended that all new applications use SHA-256 instead of one of the other hash
     functions.

     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 func-
     tions.

     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>.

BSD					September 7, 2008				      BSD
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