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