6 .Nm md5 , sha1 , sha256 , rmd160
7 .Nd calculate a message-digest fingerprint (checksum) for a file
31 .Nm md5 , sha1 , sha256
34 utilities take as input a message of arbitrary length and produce as
40 It is conjectured that it is computationally infeasible to
41 produce two messages having the same message digest, or to produce any
42 message having a given prespecified target message digest.
44 .Tn MD5 , SHA-1 , SHA-256
47 algorithms are intended for digital signature applications, where a
50 in a secure manner before being encrypted with a private
52 key under a public-key cryptosystem such as
56 has been completely broken as far as finding collisions is
57 concerned, and should not be relied upon to produce unique outputs.
60 should not be used as part of a cryptographic signature scheme.
61 At the current time (2009-01-06) there is no publicly known method to
63 MD5, i.e., to find an input given a hash value.
66 currently (2009-01-06) has no known collisions, but an attack has been
67 found which is faster than a brute-force search, placing the security of
71 It is recommended that all new applications use
73 instead of one of the other hash functions.
75 The following options may be used in any combination and must
76 precede any files named on the command line.
77 The hexadecimal checksum of each file listed on the command line is printed
78 after the options are processed.
79 .Bl -tag -width indent
81 Compare files to this md5 string.
82 (Note that this option is not yet useful if multiple files are specified.)
84 Print a checksum of the given
87 Echo stdin to stdout and append the checksum to stdout.
89 Quiet mode - only the checksum is printed out.
94 Reverses the format of the output.
95 This helps with visual diffs.
97 when combined with the
101 Run a built-in time trial.
103 Run a built-in test script.
107 .Nm md5 , sha1 , sha256
110 utilities exit 0 on success,
111 1 if at least one of the input files could not be read,
112 and 2 if at least one file does not have the same hash as the -c option.
121 .%T The MD5 Message-Digest Algorithm
126 .%T The Secure Hash Standard
130 .%A D. Eastlake and P. Jones
131 .%T US Secure Hash Algorithm 1
135 RIPEMD-160 is part of the ISO draft standard
136 .Qq ISO/IEC DIS 10118-3
137 on dedicated hash functions.
139 Secure Hash Standard (SHS):
140 .Pa http://csrc.nist.gov/cryptval/shs.html .
143 .Pa http://www.esat.kuleuven.ac.be/~bosselae/ripemd160.html .
145 This program is placed in the public domain for free general use by
148 Support for SHA-1 and RIPEMD-160 has been added by
149 .An Oliver Eikemeier Aq eik@FreeBSD.org .