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.
32 The SHA-224 , SHA-256 , SHA-384 , SHA-512, RIPEMD-160,
34 algorithms are intended for digital signature applications, where a
37 in a secure manner before being encrypted with a private
39 key under a public-key cryptosystem such as RSA.
41 The MD5 and SHA-1 algorithms have been proven to be vulnerable to practical
42 collision attacks and should not be relied upon to produce unique outputs,
43 .Em nor should they be used as part of a cryptographic signature scheme.
44 As of 2017-03-02, there is no publicly known method to
46 either algorithm, i.e., to find an input that produces a specific
49 SHA-512t256 is a version of SHA-512 truncated to only 256 bits.
50 On 64-bit hardware, this algorithm is approximately 50% faster than SHA-256 but
51 with the same level of security.
52 The hashes are not interchangeable.
54 It is recommended that all new applications use SHA-512 or SKEIN-512
55 instead of one of the other hash functions.
57 The following options may be used in any combination and must
58 precede any files named on the command line.
59 The hexadecimal checksum of each file listed on the command line is printed
60 after the options are processed.
61 .Bl -tag -width indent
63 Compare the digest of the file against this string.
64 .Pq Note that this option is not yet useful if multiple files are specified.
66 Print a checksum of the given
69 Echo stdin to stdout and append the checksum to stdout.
71 Quiet mode \(em only the checksum is printed out.
76 Reverses the format of the output.
77 This helps with visual diffs.
79 when combined with the
83 Run a built-in time trial.
85 Run a built-in test script.
89 .Nm md5 , sha1 , sha224 , sha256 , sha512 , sha512t256 , rmd160 ,
90 .Nm skein256 , skein512 ,
93 utilities exit 0 on success,
94 1 if at least one of the input files could not be read,
95 and 2 if at least one file does not have the same hash as the
99 Calculate the MD5 checksum of the string
101 .Bd -literal -offset indent
103 MD5 ("Hello") = 8b1a9953c4611296a827abf8c47804d7
106 Same as above, but note the absence of the newline character in the input
108 .Bd -literal -offset indent
109 $ echo -n Hello | md5
110 8b1a9953c4611296a827abf8c47804d7
113 Calculate the checksum of multiple files reversing the output:
114 .Bd -literal -offset indent
115 $ md5 -r /boot/loader.conf /etc/rc.conf
116 ada5f60f23af88ff95b8091d6d67bef6 /boot/loader.conf
117 d80bf36c332dc0fdc479366ec3fa44cd /etc/rc.conf
121 .Pa /boot/loader.conf
124 Then calculate the checksum again and validate it against the checksum string
128 .Bd -literal -offset indent
129 $ md5 /boot/loader.conf > digest && md5 -c $(cut -f2 -d= digest) /boot/loader.conf
130 MD5 (/boot/loader.conf) = ada5f60f23af88ff95b8091d6d67bef6
133 Same as above but comparing the digest against an invalid string
134 .Pq Dq randomstring ,
135 which results in a failure.
136 .Bd -literal -offset indent
137 $ md5 -c randomstring /boot/loader.conf
138 MD5 (/boot/loader.conf) = ada5f60f23af88ff95b8091d6d67bef6 [ Failed ]
151 .%T The MD5 Message-Digest Algorithm
156 .%T The Secure Hash Standard
160 .%A D. Eastlake and P. Jones
161 .%T US Secure Hash Algorithm 1
165 RIPEMD-160 is part of the ISO draft standard
166 .Qq ISO/IEC DIS 10118-3
167 on dedicated hash functions.
169 Secure Hash Standard (SHS):
170 .Pa http://csrc.nist.gov/cryptval/shs.html .
173 .Pa http://www.esat.kuleuven.ac.be/~bosselae/ripemd160.html .
175 This program is placed in the public domain for free general use by
178 Support for SHA-1 and RIPEMD-160 has been added by
179 .An Oliver Eikemeier Aq Mt eik@FreeBSD.org .