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

     md5 -- calculate a	message-digest fingerprint (checksum) for a file

     md5 [-pqrtx] [-s string] [file ...]

     Md5 takes as input	a message of arbitrary length and produces as output a
     128-bit ``fingerprint'' or	``message digest'' of the input.  It is	con-
     jectured 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 algorithm is intended	for
     digital 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 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	determine 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 MD5 sum 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 appends the MD5 sum to stdout.

     -q	     Quiet mode	- only the MD5 sum is printed out.  Overrides the -r

     -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.


     R.	Rivest,	The MD5	Message-Digest Algorithm, RFC1321.

     This program is placed in the public domain for free general use by RSA
     Data Security.

FreeBSD	11.1		       February	14, 1994		  FreeBSD 11.1


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