6 .Nm md5 , sha1 , sha256 , sha384 , sha512 , sha512t256 , rmd160 ,
7 .Nm skein256 , skein512 , skein1024
8 .Nd calculate a message-digest fingerprint (checksum) for a file
62 .Nm md5 , sha1 , sha256 , sha384 , sha512, sha512t256, rmd160,
63 .Nm skein256, skein512,
66 utilities take as input a message of arbitrary length and produce as
72 It is conjectured that it is computationally infeasible to
73 produce two messages having the same message digest, or to produce any
74 message having a given prespecified target message digest.
76 .Tn MD5 , SHA-1 , SHA-256 , SHA-384 , SHA-512, RIPEMD-160,
79 algorithms are intended for digital signature applications, where a
82 in a secure manner before being encrypted with a private
84 key under a public-key cryptosystem such as
91 algorithms have been proven to be vulnerable to practical collision
92 attacks and should not be relied upon to produce unique outputs, nor
93 should they be used as part of a cryptographic signature scheme.
94 As of 2017-03-02, there is no publicly known method to
96 either algorithm, i.e. to find an input that produces a specific
102 truncated to only 256 bits.
103 On 64-bit hardware, this algorithm is approximately 50% faster than
105 but with the same level of security.
106 The hashes are not interchangeable.
108 It is recommended that all new applications use
112 instead of one of the other hash functions.
114 The following options may be used in any combination and must
115 precede any files named on the command line.
116 The hexadecimal checksum of each file listed on the command line is printed
117 after the options are processed.
118 .Bl -tag -width indent
120 Compare the digest of the file against this string.
121 .Pq Note that this option is not yet useful if multiple files are specified.
123 Print a checksum of the given
126 Echo stdin to stdout and append the checksum to stdout.
128 Quiet mode \(em only the checksum is printed out.
133 Reverses the format of the output.
134 This helps with visual diffs.
136 when combined with the
140 Run a built-in time trial.
142 Run a built-in test script.
146 .Nm md5 , sha1 , sha256 , sha512, sha512t256, rmd160,
147 .Nm skein256, skein512,
150 utilities exit 0 on success,
151 1 if at least one of the input files could not be read,
152 and 2 if at least one file does not have the same hash as the
166 .%T The MD5 Message-Digest Algorithm
171 .%T The Secure Hash Standard
175 .%A D. Eastlake and P. Jones
176 .%T US Secure Hash Algorithm 1
180 RIPEMD-160 is part of the ISO draft standard
181 .Qq ISO/IEC DIS 10118-3
182 on dedicated hash functions.
184 Secure Hash Standard (SHS):
185 .Pa http://csrc.nist.gov/cryptval/shs.html .
188 .Pa http://www.esat.kuleuven.ac.be/~bosselae/ripemd160.html .
190 This program is placed in the public domain for free general use by
193 Support for SHA-1 and RIPEMD-160 has been added by
194 .An Oliver Eikemeier Aq Mt eik@FreeBSD.org .