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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] [-c string] [-s string] [file	...]
     sha1 [-pqrtx] [-c string] [-s string] [file ...]
     sha256 [-pqrtx] [-c string] [-s string] [file ...]
     rmd160 [-pqrtx] [-c string] [-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 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 secu-
     rity 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.

     -c	string
	     Compare files to this md5 string.	(Note that this	option is not
	     yet useful	if multiple files are specified.)

     -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, 1 if	at
     least one of the input files could	not be read, and 2 if at least one
     file does not have	the same hash as the -c	option.

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	9.3		       September 7, 2008		   FreeBSD 9.3

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

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