.\" $OpenBSD: rmd160.3,v 1.13 2000/12/21 17:34:33 aaron Exp $ .\" .\" Copyright (c) 1997 Todd C. Miller .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. The name of the author may not be used to endorse or promote products .\" derived from this software without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, .\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY .\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL .\" THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, .\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, .\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; .\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, .\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR .\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF .\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" .\" See http://www.esat.kuleuven.ac.be/~bosselae/ripemd160.html .\" for detailed information about RIPEMD-160. .\" .Dd July 16, 1997 .Dt RMD160 3 .Os .Sh NAME .Nm RMD160Init , .Nm RMD160Update , .Nm RMD160Final , .Nm RMD160Transform , .Nm RMD160End , .Nm RMD160File , .Nm RMD160Data .Nd calculate the ``RIPEMD-160'' message digest .Sh SYNOPSIS .Fd #include .Fd #include .Ft void .Fn RMD160Init "RMD160_CTX *context" .Ft void .Fn RMD160Update "RMD160_CTX *context" "const u_char *data" "u_int nbytes" .Ft void .Fn RMD160Final "u_char digest[20]" "RMD160_CTX *context" .Ft void .Fn RMD160Transform "u_int32_t state[5]" "const u_int32_t block[16]" .Ft "char *" .Fn RMD160End "RMD160_CTX *context" "char *buf" .Ft "char *" .Fn RMD160File "char *filename" "char *buf" .Ft "char *" .Fn RMD160Data "u_char *data" "u_int len" "char *buf" .Sh DESCRIPTION The RMD160 functions implement the 160-bit RIPE message digest hash algorithm (RMD-160). RMD-160 is used to generate a condensed representation of a message called a message digest. The algorithm takes a message less than 2^64 bits as input and produces a 160-bit digest suitable for use as a digital signature. .Pp The RMD160 functions are considered to be more secure than the .Xr md4 3 and .Xr md5 3 functions and at least as secure as the .Xr sha1 3 function. All share a similar interface. .Pp The .Fn RMD160Init function initializes a RMD160_CTX .Ar context for use with .Fn RMD160Update , and .Fn RMD160Final . The .Fn RMD160Update function adds .Ar data of length .Ar nbytes to the RMD160_CTX specified by .Ar context . .Fn RMD160Final is called when all data has been added via .Fn RMD160Update and stores a message digest in the .Ar digest parameter. When a null pointer is passed to .Fn RMD160Final as first argument only the final padding will be applied and the current context can still be used with .Fn RMD160Update . .Pp The .Fn RMD160Transform function is used by .Fn RMD160Update to hash 512-bit blocks and forms the core of the algorithm. Most programs should use the interface provided by .Fn RMD160Init , .Fn RMD160Update and .Fn RMD160Final instead of calling .Fn RMD160Transform directly. .Pp The .Fn RMD160End function is a front end for .Fn RMD160Final which converts the digest into an .Tn ASCII representation of the 160 bit digest in hexadecimal. .Pp The .Fn RMD160File function calculates the digest for a file and returns the result via .Fn RMD160End . If .Fn RMD160File is unable to open the file a NULL pointer is returned. .Pp The .Fn RMD160Data function calculates the digest of an arbitrary string and returns the result via .Fn RMD160End . .Pp For each of the .Fn RMD160End , .Fn RMD160File , and .Fn RMD160Data functions the .Ar buf parameter should either be a string of at least 41 characters in size or a NULL pointer. In the latter case, space will be dynamically allocated via .Xr malloc 3 and should be freed using .Xr free 3 when it is no longer needed. .Sh EXAMPLES The follow code fragment will calculate the digest for the string "abc" which is ``0x8eb208f7e05d987a9b044a8e98c6b087f15a0bfc''. .Bd -literal -offset indent RMD160_CTX rmd; u_char results[20]; char *buf; int n; buf = "abc"; n = strlen(buf); RMD160Init(&rmd); RMD160Update(&rmd, (u_char *)buf, n); RMD160Final(results, &rmd); /* Print the digest as one long hex value */ printf("0x"); for (n = 0; n < 20; n++) printf("%02x", results[n]); putchar('\en'); .Ed .Pp Alternately, the helper functions could be used in the following way: .Bd -literal -offset indent RMD160_CTX rmd; u_char output[41]; char *buf = "abc"; printf("0x%s\en", RMD160Data(buf, strlen(buf), output)); .Ed .Sh CAVEATS If a message digest is to be copied to a multi-byte type (ie: an array of five 32-bit integers) it will be necessary to perform byte swapping on little endian machines such as the i386, alpha, and vax. .Sh AUTHOR This implementation of RMD-160 was written by Antoon Bosselaers. .Pp The .Fn RMD160End , .Fn RMD160File , and .Fn RMD160Data helper functions are derived from code written by Poul-Henning Kamp. .Sh SEE ALSO .Xr rmd160 1 , .Xr md4 3 , .Xr md5 3 , .Xr sha1 3 .Pp .Rs .%A H. Dobbertin, A. Bosselaers, B. Preneel .%T RIPEMD-160, a strengthened version of RIPEMD .Re .Rs .%T Information technology - Security techniques - Hash-functions - Part 3: Dedicated hash-functions .%O ISO/IEC 10118-3 .Re .Rs .%A H. Dobbertin, A. Bosselaers, B. Preneel .%T The RIPEMD-160 cryptographic hash function .%J Dr. Dobb's Journal .%V Vol. 22, No. 1 .%D January 1997 .%P pp. 24-28 .Re .Sh HISTORY The RMD-160 functions appeared in .Ox 2.1 .