md5 - calculate a message-digest fingerprint (checksum) for
md5 [-p | -t | -x | -c [checklist ...] | -s string | file
md5 takes as input a message of arbitrary length and produces as output a
128-bit "fingerprint" or "message digest" of the input. It
that it would be computationally infeasible to produce
having the same message digest (a collision), or to produce
having a given prespecified target message digest. However,
have now been produced for MD5, so the use of other message
such as sha1(1), is now preferred.
The MD5 algorithm is intended for digital signature applications, where a
large file must be "compressed" in a secure manner before
with a private (secret) key under a public-key cryptosystem
such as RSA.
The options are as follows:
-c [checklist ...]
Compares all checksums contained in the file
checklist with newly
computed checksums for the corresponding files.
of the digest used, the file name, and an OK or
FAILED for the
result of the comparison. This will validate any of
checksums (see cksum(1)). If no file is given,
stdin is used.
-p Echoes stdin to stdout and appends the MD5 sum to
Prints a checksum of the given string.
-t Runs a built-in time trial.
-x Runs a built-in test script.
The MD5 sum of each file listed on the command line is
printed after the
options are processed.
cksum(1), rmd160(1), sha1(1)
R. Rivest, The MD5 Message-Digest Algorithm, RFC 1321.
Since collisions have been found for MD5, the use of sha1(1)
OpenBSD 3.6 April 30, 2004
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