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

     md5, sha1,	sha256,	sha512,	rmd160 -- calculate a message-digest finger-
     print (checksum) for a file


     The md5, sha1, sha256, sha512 and rmd160 utilities	take as	input a	mes-
     sage of arbitrary length and produce as output a ``fingerprint'' or
     ``message digest''	of the input.  It is conjectured that it is computa-
     tionally infeasible to produce two	messages having	the same message
     digest, or	to produce any message having a	given prespecified target mes-
     sage digest.  The MD5, SHA-1, SHA-256, SHA-512 and	RIPEMD-160 algorithms
     are intended for digital signature	applications, where a large file must

     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.

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


     -c	string

     -s	string
	     Print a checksum of the given string.



	     Does nothing when combined	with the -ptx options.

     -t	     Run a built-in time trial.

     -x	     Run a built-in test script.

     The md5, sha1, sha256, sha512 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.

     cksum(1), md5(3), ripemd(3), sha(3), sha256(3), sha512(3)




     dedicated hash functions.

     Secure Hash Standard (SHS):

     The RIPEMD-160 page:

     Data Security.


FreeBSD	10.2			 May 17, 2014			  FreeBSD 10.2


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