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sha1(1)

NAME

     md5, sha1, rmd160 -- calculate a message-digest fingerprint (checksum)
     for a file

SYNOPSIS

     md5 [-pqrtx] [-s string] [file ...]
     sha1 [-pqrtx] [-s string] [file ...]
     rmd160 [-pqrtx] [-s string] [file ...]

DESCRIPTION

     The md5, sha1 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 prespecified target message digest.  The MD5,
     SHA-1 and RIPEMD-160 algorithms are intended for digital signature appli-
     cations, 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 hexadecimal checksum 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 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.

DIAGNOSTICS

     The md5, sha1 and rmd160 utilities exit 0 on success, and 1 if at least
     one of the input files could not be read.

SEE ALSO

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

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

     J. Burrows, The Secure Hash Standard, FIPS PUB 180-1.

     D. Eastlake and P. Jones, US Secure Hash Algorithm 1, RFC 3174.

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 5.4			 June 6, 2004			   FreeBSD 5.4

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