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 md5 9.Op Fl ptx 10.Op Fl s Ar string 11.Op Ar file ... 12.Sh DESCRIPTION 13.Nm Md5 14takes as input a message of arbitrary length and produces 15as output a 128-bit 16.Dq fingerprint 17or 18.Dq message digest 19of the input. It is conjectured that it is computationally infeasible to 20produce two messages having the same message digest, or to produce any 21message having a given prespecified target message digest. 22The MD5 algorithm is intended for digital signature applications, where a 23large file must be 24.Dq compressed 25in a secure manner before being encrypted with a private 26.Pq secret 27key under a public-key cryptosystem such as 28.Em RSA . 29.Pp 30The following four options may be used in any combination and must 31precede any files named on the command line. The MD5 32sum of each file listed on the command line is printed after the options 33are processed. 34.Bl -tag -width indent 35.It Fl s Ar string 36Print a checksum of the given 37.Ar string . 38.It Fl p 39Echo stdin to stdout and appends the MD5 sum to stdout. 40.It Fl t 41Run a built-in time trial. 42.It Fl x 43Run a built-in test script. 44.El 45.Sh SEE ALSO 46.Xr cksum 1 47.Rs 48.%A R. Rivest 49.%T The MD5 Message-Digest Algorithm 50.%O RFC1321 51.Re 52.Sh ACKNOWLEDGMENTS 53This program is placed in the public domain for free general use by 54RSA Data Security. 55