MD5(1) | General Commands Manual | MD5(1) |
md5
— calculate a
message-digest fingerprint (checksum) for a file
md5 |
[-pqrtx ] [-s
string] [file ...] |
The md5
utility takes as input a message
of arbitrary length and produces as output a “fingerprint” or
“message digest” of the input. It is conjectured that it is
computationally infeasible to produce two messages having the same message
digest, or to produce any message having a given prespecified target message
digest. The MD5 algorithm is intended for digital signature applications,
where a large file must be “compressed” in a secure manner
before being encrypted with a private (secret) key under a public-key
cryptosystem such as RSA.
MD5's designer Ron Rivest has stated "md5 and sha1 are both clearly broken (in terms of collision-resistance)". So MD5 should be avoided when creating new protocols, or implementing protocols with better options. SHA256 and SHA512 are better options as they have been more resilient to attacks (as of 2009).
The following options may be used in any combination and must precede any files named on the command line. The hexadecimal checksum of each file listed on the command line is printed after the options are processed.
-s
string-p
-q
-r
option.-r
-ptx
options.-t
-x
The md5
utility exits 0 on success, and 1
if at least one of the input files could not be read.
cksum(1), CC_SHA256_Init(3), md5(3), ripemd(3), sha(3)
R. Rivest, The MD5 Message-Digest Algorithm, RFC1321.
Vlastimil Klima, Finding MD5 Collisions - a Toy For a Notebook, Cryptology ePrint Archive: Report 2005/075.
This program is placed in the public domain for free general use by RSA Data Security.
June 6, 2004 | macOS 14.6 |