Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
MD5(1)			  BSD General Commands Manual			MD5(1)

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

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

DESCRIPTION
     The md5 utility takes as input a message of arbitrary length and produces
     as	output a 128-bit "fingerprint" or "message digest" of the input.  It
     is	conjectured that it is computationally infeasible to produce two mes-
     sages 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 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 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
	     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.

SEE ALSO
     cksum(1)

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

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

BSD			       February	14, 1994			   BSD

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | ACKNOWLEDGMENTS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=md5&sektion=1&manpath=FreeBSD+5.0-RELEASE>

home | help