md5.1 revision 28935 
1.Dd February 14, 1994
2.Dt MD5 1
3.Os
4.Sh NAME
5.Nm md5
6.Nd calculate a message-digest fingerprint (checksum) for a file
7.Sh SYNOPSIS
8.Nm
9.Op Fl p
10.Op Fl t
11.Op Fl x
12.Op Fl s Ns Ar string
13.Op Ar filename Ns Pq s
14.Sh DESCRIPTION
15.Nm
16takes as input a message of arbitrary length and produces
17as output a 128-bit
18.Dq fingerprint
19or
20.Dq message digest
21of the input.  It is conjectured that it is computationally infeasible to
22produce two messages having the same message digest, or to produce any
23message having a given prespecified target message digest.
24The MD5 algorithm is intended for digital signature applications, where a
25large file must be
26.Dq compressed
27in a secure manner before being encrypted with a private
28.Pq secret
29key under a public-key cryptosystem such as
30.Em RSA .
31.Pp
32The following four options may be used in any combination, except
33that
34.Ar filename Ns Pq s
35must be the last objects on the command line.
36.Bl -tag -width Fl
37.It Fl s Ns Ar string
38prints a checksum of the given
39.Dq string .
40.It Fl p
41echos stdin to stdout and appends the MD5 sum to stdout.
42.It Fl t
43runs a built-in time trial.
44.It Fl x
45runs a built-in test script.
46.It Ar filename Ns Pq s
47prints a checksum
48.Pq s
49for each of the files.
50.El
51.Sh SEE ALSO
52.Xr cksum 1
53.Rs
54.%A R. Rivest
55.%T The MD5 Message-Digest Algorithm
56.%O RFC1321
57.Re
58.Sh ACKNOWLEDGEMENTS
59This program is placed in the public domain for free general use by
60RSA Data Security.
61