6 .Nm md5 , sha1 , sha224 , sha256 , sha384 , sha512 , sha512t256 , rmd160 ,
7 .Nm skein256 , skein512 , skein1024
8 .Nd calculate a message-digest fingerprint (checksum) for a file
16 (All other hashes have the same options and usage.)
19 .Nm md5 , sha1 , sha224 , sha256 , sha384 , sha512, sha512t256, rmd160,
20 .Nm skein256, skein512,
23 utilities take as input a message of arbitrary length and produce as
29 It is conjectured that it is computationally infeasible to
30 produce two messages having the same message digest, or to produce any
31 message having a given prespecified target message digest.
33 .Tn SHA-224 , SHA-256 , SHA-384 , SHA-512, RIPEMD-160,
36 algorithms are intended for digital signature applications, where a
39 in a secure manner before being encrypted with a private
41 key under a public-key cryptosystem such as
48 algorithms have been proven to be vulnerable to practical collision
49 attacks and should not be relied upon to produce unique outputs,
50 .Em nor should they be used as part of a cryptographic signature scheme.
51 As of 2017-03-02, there is no publicly known method to
53 either algorithm, i.e. to find an input that produces a specific
59 truncated to only 256 bits.
60 On 64-bit hardware, this algorithm is approximately 50% faster than
62 but with the same level of security.
63 The hashes are not interchangeable.
65 It is recommended that all new applications use
69 instead of one of the other hash functions.
71 The following options may be used in any combination and must
72 precede any files named on the command line.
73 The hexadecimal checksum of each file listed on the command line is printed
74 after the options are processed.
75 .Bl -tag -width indent
77 Compare the digest of the file against this string.
78 .Pq Note that this option is not yet useful if multiple files are specified.
80 Print a checksum of the given
83 Echo stdin to stdout and append the checksum to stdout.
85 Quiet mode \(em only the checksum is printed out.
90 Reverses the format of the output.
91 This helps with visual diffs.
93 when combined with the
97 Run a built-in time trial.
99 Run a built-in test script.
103 .Nm md5 , sha1 , sha224 , sha256 , sha512 , sha512t256 , rmd160 ,
104 .Nm skein256 , skein512,
107 utilities exit 0 on success,
108 1 if at least one of the input files could not be read,
109 and 2 if at least one file does not have the same hash as the
124 .%T The MD5 Message-Digest Algorithm
129 .%T The Secure Hash Standard
133 .%A D. Eastlake and P. Jones
134 .%T US Secure Hash Algorithm 1
138 RIPEMD-160 is part of the ISO draft standard
139 .Qq ISO/IEC DIS 10118-3
140 on dedicated hash functions.
142 Secure Hash Standard (SHS):
143 .Pa http://csrc.nist.gov/cryptval/shs.html .
146 .Pa http://www.esat.kuleuven.ac.be/~bosselae/ripemd160.html .
148 This program is placed in the public domain for free general use by
151 Support for SHA-1 and RIPEMD-160 has been added by
152 .An Oliver Eikemeier Aq Mt eik@FreeBSD.org .