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The MD4 Message-Digest Algorithm (RFC1320)

IP.com Disclosure Number: IPCOM000002142D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2019-Feb-11
Document File: 20 page(s) / 22K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

R. Rivest: AUTHOR

Related Documents

10.17487/RFC1320: DOI

Abstract

This document describes the MD4 message-digest algorithm [1]. The algorithm takes as input a message of arbitrary length and produces as output a 128-bit "fingerprint" or "message digest" of the input. This memo provides information for the Internet community. It does not specify an Internet standard.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 12% of the total text.

Network Working Group R. Rivest Request for Comments: 1320 MIT Laboratory for Computer Science Obsoletes: RFC 1186 and RSA Data Security, Inc. April 1992

The MD4 Message-Digest Algorithm

Status of thie Memo

This memo provides information for the Internet community. It does not specify an Internet standard. Distribution of this memo is unlimited.

Acknowlegements

We would like to thank Don Coppersmith, Burt Kaliski, Ralph Merkle, and Noam Nisan for numerous helpful comments and suggestions.

Table of Contents

1. Executive Summary 1 2. Terminology and Notation 2 3. MD4 Algorithm Description 2 4. Summary 6 References 6 APPENDIX A - Reference Implementation 6 Security Considerations 20 Author’s Address 20

1. Executive Summary

This document describes the MD4 message-digest algorithm [1]. 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 MD4 algorithm is intended for digital signature applications, where a large file must be "compressed" in a secure manner before being encrypted with a private (secret) key under a public-key cryptosystem such as RSA.

The MD4 algorithm is designed to be quite fast on 32-bit machines. In addition, the MD4 algorithm does not require any large substitution tables; the algorithm can be coded quite compactly.

Rivest [Page 1]

RFC 1320 MD4 Message-Digest Algorithm April 1992

The MD4 algorithm is being placed in the public domain for review and possible adoption as a standard.

This document replaces the October 1990 RFC 1186 [2]. The main difference is that the reference implementation of MD4 in the appendix is more portable.

For OSI-based applications, MD4’s object identifier is

md4 OBJECT IDENTIFIER ::= {iso(1) member-body(2) US(840) rsadsi(113549) digestAlgorithm(2) 4}

In the X.509 type AlgorithmIdentifier [3], the parameters for MD4 should have type NULL.

2. Terminology and Notation

In this document a "word" is a 32-bit quantity and a "byte" is an eight-bit quantity. A sequence of bits can be interpreted in a natural manner as a sequence of bytes, where each consecutive group of eight bits is interpreted as a byte with the high-order (most significant) bit of each byte listed first. Similarly, a sequence of bytes can be interpreted as a sequence of 32-bit words, where each consecutive group of four bytes is interpreted as a word with the low-order (least significant) byte given first.

Let x_i denote "x sub i". If the subscript is an expression, we surround it in braces, as in x_{i+1}. Similarly, we use ^ for superscripts (exponentiation), so that x^i denotes x to the i-th power.

Let the symbol "+" denote addition of words (i.e., modulo-2^32 addition). Let X <<< s denote the 32-bit value obtained by circularly shifting (rotating) X left by s bit...

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