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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 ar-
     bitrary 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 signa-
     ture 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 de-
     termine 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>.

BSD				 June 6, 2004				   BSD

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

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