1. Executive Summary

This document describes the MD2 message-digest algorithm. The algorithm takes as input a message of arbitrary length and produces as output a 128-bit "fingerprint" or "message digest" of the input. It is conjectured that it is computationally infeasible to produce two messages having the same message digest, or to produce any message having a given prespecified target message digest. The MD2 algorithm is intended for digital signature applications, where a large file must be "compressed" in a secure manner before being signed with a private (secret) key under a public-key cryptosystem such as RSA.

License to use MD2 is granted for non-commerical Internet Privacy- Enhanced Mail [1,2,3].

This document is an update to the August 1989 RFC 1115^hist(-> 1423^hist) [3], which also gives a reference implementation of MD2. The main differences are that a textual description of MD2 is included, and that the reference implementation of MD2 is more portable.

For OSI-based applications, MD2's object identifier is

   md2 OBJECT IDENTIFIER ::=
   iso(1) member-body(2) US(840) rsadsi(113549) digestAlgorithm(2) 2}

In the X.509 type AlgorithmIdentifier [4], the parameters for MD2 should have type NULL.