MD4 is a message digest algorithm (the fourth in a series) designed by Professor Ronald Rivest of MIT in 1990. It implements a cryptographic hash function for use in message integrity checks. The digest length is 128 bits. The algorithm has influenced later designs, such as the MD5, SHA and RIPEMD algorithms. Flowcharts are often used to represent algorithms. ... Professor Ron Rivest Professor Ronald Linn Rivest (born 1947, Schenectady, New York) is a cryptographer, and is the Viterbi Professor of Computer Science at MITs Department of Electrical Engineering and Computer Science. ... The Massachusetts Institute of Technology, or MIT, is a university located in the city of Cambridge, Massachusetts, USA. MIT is one of the worlds leading research institutions in science and technology, as well as in numerous other fields, including management, economics, linguistics, political science, and philosophy. ... In cryptography, a cryptographic hash function is a hash function with certain additional security properties to make it suitable for use as a primitive in various information security applications, such as authentication and message integrity. ... In cryptography, MD5 (Message-Digest algorithm 5) is a widely-used cryptographic hash function with a 128-bit hash value. ... Sha (Ш, ш) is a letter of the Cyrillic alphabet, representing the consonant sound /ʃ/ or /ʃʲ/. This is equivalent to sh in English, ch in French, sch in German, ş in Turkish, or sz in Polish. ... RIPEMD-160 (RACE Integrity Primitives Evaluation Message Digest) is a 160-bit message digest algorithm (and cryptographic hash function) developed in Europe by Hans Dobbertin, Antoon Bosselaers and Bart Preneel, and first published in 1996. ...

Weaknesses in MD4 were demonstrated by Den Boer and Bosselaers in a paper published in 1991. In August 2004, researchers reported generating collisions in MD4 using "hand calculation" [1], alongside attacks on later hash function designs in the MD4/MD5/SHA/RIPEMD family. 1991 (MCMXCI) was a common year starting on Tuesday of the Gregorian calendar. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... In computer science, a hash collision is a situation that occurs when two distinct inputs into a hash function produce identical outputs. ...

MD4 hashes

The 128-bit (16-byte) MD4 hashes (also termed message digests) are typically represented as 32-digit hexadecimal numbers. The following demonstrates a 43-byte ASCII input and the corresponding MD4 hash: In mathematics and computer science, hexadecimal, or simply hex, is a numeral system with a radix or base of 16 usually written using the symbols 0–9 and A–F or a–f. ... For other uses, see ASCII (disambiguation). ...

 MD4("The quick brown fox jumps over the lazy dog") = 1bee69a46ba811185c194762abaeae90 

Even a small change in the message will (with overwhelming probability) result in a completely different hash, e.g. changing d to c:

 MD4("The quick brown fox jumps over the lazy cog") = b86e130ce7028da59e672d56ad0113df 

The hash of the zero-length string is:

 MD4("") = 31d6cfe0d16ae931b73c59d7e0c089c0 

See also

• MD2
• Jacksum — written in Java. Various message verification functions, including MD4. Released under the GPL.

Message Digest Algorithm 2 (MD2) is a cryptographic hash function developed by Ronald Rivest in 1989. ... Java is an object-oriented programming language developed by James Gosling and colleagues at Sun Microsystems in the early 1990s. ... The GNU logo For other uses of GPL, see GPL (disambiguation). ...

References

• Hans Dobbertin, 1998. Cryptanalysis of MD4. J. Cryptology 11(4): 253–271
• Hans Dobbertin: Cryptanalysis of MD4. Fast Software Encryption 1996: 53–69

External links

• Description of MD4 by Ron Rivest in RFC 1320
• An Attack on the Last Two Rounds of MD4
• A collision attack on MD4 (Presented at Eurocrypt 2005. Requires about 2¹⁴ MD4 computations. Demonstrates "Theoretical Pre-image Attack on MD4" and "Second Pre-Image Attack for Weak Messages".)
• On the Security of Encryption Modes of MD4, MD5 and HAVAL ("MD4 [...] can be broken by related-key boomerang attacks in real time. The attacks have been experimentally tested and run in milliseconds on a PC.")
• Improved Collision Attack on MD4 ("We were able to find collisions with probability almost 1, and the average complexity to find a collision is upper bounded by three times of MD4 hash operations.")
• Serversniff.net Online-Tool to compute MD4-Hashes from strings
• Paj's Home: Cryptography — by Paj in JavaScript. Also supports MD5, and SHA-1. Released under the BSD License. Contains links to several other implementations.

2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... In cryptography, a preimage attack on a cryptographic hash differs from a collision attack. ... In cryptography, a related-key attack is any form of cryptanalysis which presumes that the attacker has the capability to consider the operation of a cipher under several different keys. ... In cryptography, the boomerang attack is a method for the cryptanalysis of block ciphers, based on differential cryptanalysis invented by David Wagner in 1999. ... JavaScript is the name of Netscapes implementation of ECMAScript, a scripting programming language based on the concept of prototypes. ... In cryptography, MD5 (Message-Digest algorithm 5) is a widely-used cryptographic hash function with a 128-bit hash value. ... The SHA (Secure Hash Algorithm) family is a set of related cryptographic hash functions designed by the National Security Agency (NSA) and published by the National Institute of Standards and Technology (NIST). ... The BSD license is an acronym for the Berkeley Software Distribution license agreement, and is one of the most widely used licenses for free software (a subset of open source software). ...

Collisions

• Fast MD4 Collision Generator