1.\" $OpenBSD: md5.1,v 1.11 2001/06/03 17:51:29 millert Exp $ 2.\" 3.Dd June 4, 2001 4.Dt MD5 1 5.Os 6.Sh NAME 7.Nm md5 8.Nd calculate a message-digest fingerprint (checksum) for a file 9.Sh SYNOPSIS 10.Nm md5 11.Oo 12.Fl p | Fl t | Fl x | 13.Fl s Ar string | Ar file ... 14.Oc 15.Sh DESCRIPTION 16.Nm 17takes as input a message of arbitrary length and produces 18as output a 128-bit "fingerprint" or "message digest" of the input. 19It is conjectured that it is computationally infeasible to produce 20two messages having the same message digest, or to produce any 21message having a given prespecified target message digest. 22.Pp 23The 24.Em MD5 25algorithm is intended for digital signature applications, where a 26large file must be "compressed" in a secure manner before being 27encrypted with a private (secret) key under a public-key cryptosystem 28such as 29.Em RSA . 30.Pp 31The options are as follows: 32.Bl -tag -width Ds 33.It Fl s Ar string 34Prints a checksum of the given 35.Ar string . 36.It Fl p 37Echos stdin to stdout and appends the 38.Em MD5 39sum to stdout. 40.It Fl t 41Runs a built-in time trial. 42.It Fl x 43Runs a built-in test script. 44.El 45.Pp 46The MD5 sum of each file listed on the command line is printed after the 47options are processed. 48.Sh SEE ALSO 49.Xr cksum 1 , 50.Xr rmd160 1 , 51.Xr sha1 1 52.Pp 53RFC 1321 describes in detail the MD2, MD4, and MD5 message-digest algorithms. 54