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

NAME
     md5, sha1,	sha256,	sha384,	sha512,	sha512t256, rmd160 -- calculate	a mes-
     sage-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 ...]
     sha384 [-pqrtx] [-c string] [-s string] [file ...]
     sha512 [-pqrtx] [-c string] [-s string] [file ...]
     sha512t256	[-pqrtx] [-c string] [-s string] [file ...]
     rmd160 [-pqrtx] [-c string] [-s string] [file ...]

DESCRIPTION
     The md5, sha1, sha256, sha384, sha512, sha512t256 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 prespeci-
     fied target message digest.  The MD5, SHA-1, SHA-256, SHA-384, SHA-512
     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 (2014-05-17) there is no publicly known method	to
     ``reverse'' MD5, i.e., to find an input given a hash value.

     SHA-1 currently (2014-05-17) 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.

     SHA-512t256 is a version of SHA-512 truncated to only 256 bits.  On
     64-bit hardware, this algorithm is	approximately 50% faster than SHA-256
     but with the same level of	security.  The hashes are not interchangeable.

     It	is recommended that all	new applications use SHA-512 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 the digest	of the file against this 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, sha512, sha512t256 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), sha384(3),	sha512(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	11.1			April 22, 2016			  FreeBSD 11.1

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

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