freebsd/sbin/md5/md5.1

.\" $FreeBSD$
.Dd February 14, 1994
.Dt MD5 1
.Os
.Sh NAME
.Nm md5
.Nd calculate a message-digest fingerprint (checksum) for a file
.Sh SYNOPSIS
.Nm
.Op Fl pqrtx
.Op Fl s Ar string
.Op Ar
.Sh DESCRIPTION
The
.Nm
utility takes as input a message of arbitrary length and produces
as output a 128-bit
.Dq fingerprint
or
.Dq 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 algorithm is intended for digital signature applications, where a
large file must be
.Dq compressed
in a secure manner before being encrypted with a private
(secret)
key under a public-key cryptosystem such as
.Em RSA .
.Pp
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
.Dq collisions
\(em 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.
.Pp
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.
.Bl -tag -width indent
.It Fl s Ar string
Print a checksum of the given
.Ar string .
.It Fl p
Echo stdin to stdout and appends the MD5 sum to stdout.
.It Fl q
Quiet mode - only the MD5 sum is printed out.
Overrides the
.Fl r
option.
.It Fl r
Reverses the format of the output.
This helps with visual diffs.
Does nothing
when combined with the
.Fl ptx
options.
.It Fl t
Run a built-in time trial.
.It Fl x
Run a built-in test script.
.El
.Sh DIAGNOSTICS
The
.Nm
utility exits 0 on success,
and 1 if at least one of the input files could not be read.
.Sh SEE ALSO
.Xr cksum 1
.Rs
.%A R. Rivest
.%T The MD5 Message-Digest Algorithm
.%O RFC1321
.Re
.Sh ACKNOWLEDGMENTS
This program is placed in the public domain for free general use by
RSA Data Security.
Add a new "-r" (right) option that reverses the order a filename and the hash is printed. This aids visual diffs. 1999-11-07 04:14:55 +00:00			`.\" $FreeBSD$`
fix a few spelling changes Submitted by: Josh Gilliam Closes PR's: 4429, 4431-4438 PS: He has agreed to submit all contrib fixes back to the original author. 1997-08-30 12:22:49 +00:00			`.Dd February 14, 1994`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`.Dt MD5 1`
			`.Os`
			`.Sh NAME`
			`.Nm md5`
			`.Nd calculate a message-digest fingerprint (checksum) for a file`
			`.Sh SYNOPSIS`
mdoc(7) police: use the new features of the Nm macro. 2000-11-20 16:52:27 +00:00			`.Nm`
Add -q quite mode. 1999-12-04 01:29:43 +00:00			`.Op Fl pqrtx`
Get md5(1) to use getopt(3). Also some minor -Wall cleaning while here. PR: 5387 Submitted by: Matthew Hunt <mph@pobox.com> 1997-12-29 03:40:37 +00:00			`.Op Fl s Ar string`
mdoc(7) police: use the default ``file ...'' feature of the .Ar macro. 2001-02-13 09:56:35 +00:00			`.Op Ar`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`.Sh DESCRIPTION`
Use `The .Nm utility' 2002-04-19 23:06:29 +00:00			`The`
			`.Nm`
			`utility takes as input a message of arbitrary length and produces`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`as output a 128-bit`
			`.Dq fingerprint`
			`or`
			`.Dq message digest`
mdoc(7) police: removed hard sentence breaks. 2001-09-04 09:28:48 +00:00			`of the input.`
			`It is conjectured that it is computationally infeasible to`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`produce two messages having the same message digest, or to produce any`
Incorproate version of md5 placed into public domain by RSA. 1994-10-29 23:58:02 +00:00			`message having a given prespecified target message digest.`
			`The MD5 algorithm is intended for digital signature applications, where a`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`large file must be`
			`.Dq compressed`
			`in a secure manner before being encrypted with a private`
mdoc(7) police: Avoid using parenthesis enclosure macros (.Pq and .Po/.Pc) with plain text. Not only this slows down the mdoc(7) processing significantly, but it also has an undesired (in this case) effect of disabling hyphenation within the entire enclosed block. 2001-08-07 15:48:51 +00:00			`(secret)`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`key under a public-key cryptosystem such as`
			`.Em RSA .`
			`.Pp`
Mention collision attacks on MD5. From the md5(3) man page. PR: docs/14158 Reviewed by: kris Submitted by: Eric Frias <efrias@sg505.net> 2001-09-04 01:01:07 +00:00			`MD5 has not yet (2001-09-03) been broken, but sufficient attacks have been`
mdoc(7) police: removed hard sentence breaks. 2001-09-04 09:28:48 +00:00			`made that its security is in some doubt.`
			`The attacks on MD5`
			`are in the nature of finding`
			`.Dq collisions`
			`\(em that is, multiple`
Mention collision attacks on MD5. From the md5(3) man page. PR: docs/14158 Reviewed by: kris Submitted by: Eric Frias <efrias@sg505.net> 2001-09-04 01:01:07 +00:00			`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.`
			`.Pp`
This command has more than four options. 2001-06-19 03:34:03 +00:00			`The following options may be used in any combination and must`
mdoc(7) police: removed hard sentence breaks. 2001-09-04 09:28:48 +00:00			`precede any files named on the command line.`
			`The MD5`
Get md5(1) to use getopt(3). Also some minor -Wall cleaning while here. PR: 5387 Submitted by: Matthew Hunt <mph@pobox.com> 1997-12-29 03:40:37 +00:00			`sum of each file listed on the command line is printed after the options`
			`are processed.`
Correct use of .Nm. Spelling. Add rcsid, remove unused #includes, use err(3). 1998-07-06 07:04:50 +00:00			`.Bl -tag -width indent`
Get md5(1) to use getopt(3). Also some minor -Wall cleaning while here. PR: 5387 Submitted by: Matthew Hunt <mph@pobox.com> 1997-12-29 03:40:37 +00:00			`.It Fl s Ar string`
Correct use of .Nm. Spelling. Add rcsid, remove unused #includes, use err(3). 1998-07-06 07:04:50 +00:00			`Print a checksum of the given`
Get md5(1) to use getopt(3). Also some minor -Wall cleaning while here. PR: 5387 Submitted by: Matthew Hunt <mph@pobox.com> 1997-12-29 03:40:37 +00:00			`.Ar string .`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`.It Fl p`
Correct use of .Nm. Spelling. Add rcsid, remove unused #includes, use err(3). 1998-07-06 07:04:50 +00:00			`Echo stdin to stdout and appends the MD5 sum to stdout.`
Add -q quite mode. 1999-12-04 01:29:43 +00:00			`.It Fl q`
mdoc(7) police: removed hard sentence breaks. 2001-09-04 09:28:48 +00:00			`Quiet mode - only the MD5 sum is printed out.`
			`Overrides the`
Add -q quite mode. 1999-12-04 01:29:43 +00:00			`.Fl r`
			`option.`
Add a new "-r" (right) option that reverses the order a filename and the hash is printed. This aids visual diffs. 1999-11-07 04:14:55 +00:00			`.It Fl r`
mdoc(7) police: removed hard sentence breaks. 2001-09-04 09:28:48 +00:00			`Reverses the format of the output.`
			`This helps with visual diffs.`
			`Does nothing`
Remove whitespace at EOL. 2001-07-15 07:53:42 +00:00			`when combined with the`
Make `-r -s' also match the BSDI output. 1999-11-11 11:59:03 +00:00			`.Fl ptx`
Add a new "-r" (right) option that reverses the order a filename and the hash is printed. This aids visual diffs. 1999-11-07 04:14:55 +00:00			`options.`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`.It Fl t`
Correct use of .Nm. Spelling. Add rcsid, remove unused #includes, use err(3). 1998-07-06 07:04:50 +00:00			`Run a built-in time trial.`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`.It Fl x`
Correct use of .Nm. Spelling. Add rcsid, remove unused #includes, use err(3). 1998-07-06 07:04:50 +00:00			`Run a built-in test script.`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`.El`
Set exit code to 1 in case at least one of the input files could not be opened. 2003-11-02 23:12:08 +00:00			`.Sh DIAGNOSTICS`
			`The`
			`.Nm`
Assorted markup, grammar, and spelling fixes. 2004-05-17 08:35:43 +00:00			`utility exits 0 on success,`
			`and 1 if at least one of the input files could not be read.`
mdoc'ify man page 1997-03-02 21:43:10 +00:00			`.Sh SEE ALSO`
			`.Xr cksum 1`
			`.Rs`
			`.%A R. Rivest`
			`.%T The MD5 Message-Digest Algorithm`
			`.%O RFC1321`
			`.Re`
Correct use of .Nm. Spelling. Add rcsid, remove unused #includes, use err(3). 1998-07-06 07:04:50 +00:00			`.Sh ACKNOWLEDGMENTS`
Incorproate version of md5 placed into public domain by RSA. 1994-10-29 23:58:02 +00:00			`This program is placed in the public domain for free general use by`
			`RSA Data Security.`