Feb 18, 2019 · MD4 replaced MD2 despite the fact that MD4 is more badly broken. Even MD5, an improvement upon MD4, is more badly broken than MD2 is! The best collision attack against MD2 has a time complexity of 2 63.3 compression function evaluations and a memory requirement of 2 52 hash values, which is only slightly better than the birthday attack and not ...

Apr 9, 2013 · Actually, HMAC might still be secure for a hash function that is broken (with respect to the requirements of a cryptographic hash function, such as primary preimage resistance, secondary preimage resistance and collision resistance), but it must not be too badly broken.

Jul 8, 2018 · In the MD4 algorithm, the message which is being hashed is split into a series of 512-bit blocks. The collision attack which you reference forms a collision in a single block. That is, the attack forms two colliding messages, X and X', which are identical for every block but one.

Aug 26, 2014 · MD5 and SHA-1 have a lot in common; SHA-1 was clearly inspired on either MD5 or MD4, or both (SHA-1 is a patched version of SHA-0, which was published in 1993, while MD5 was described as a RFC in 1992). The main structural differences are the following: SHA-1 has a larger state: 160 bits vs 128 bits. SHA-1 has more rounds: 80 vs 64.

Mar 1, 2019 · Just reading Ron Rivest's explanation of MD4 the hash uses two round constants one $ \text{5A827999}$ on round $2$ and the other $\text{6ED9EBA1}$ on round $3$. I think they are supposed to be hex representation of square root of $2$ and $3$. But $\sqrt{2} = 1.\text{6A09E667F} $ and $\sqrt{3} = 1.\text{BB67AE858}$

Jan 22, 2024 · M.J.B. Robshaw, “MD2, MD4, MD5, SHA, and Other Hash Functions,” Technical Report TR–101, Version 3.0, RSA Laboratories, Jul 1994. I couldn't find a soft copy at a quick first look. Here is a related question and answer here which is about MD1 but a …

Aug 31, 2013 · It suggests MD1 as such never existed, but was instead just MD (and was never published) and that MD3 was a failed experiment; apparently there exists a specification somewhere (I cannot find the referenced document 1335: MD2, MD4, MD5, SHA and other hash functions. M.J.B. Robshaw).

Initially there was MD4, then MD5; MD5 was designed later, but both were published as open standards simultaneously. MD5 had been designed because of suspected weaknesses in MD4 (which were very real !). So MD5 was the first (and, at that time, believed secure) efficient hash function with a public, readable specification.

The latest I know about is indeed "MD4 is Not One-Way."by Gaëtan Leurent (PDF) FSE 2008.Some of the more interesting and more recent publications to check on are "Advanced Meet-in-the-Middle Preimage Attacks: First Results on Full Tiger, and Improved Results on MD4 and SHA-2", Jian Guo/San Ling/Christian Rechberger/Huaxiong Wang, 2010 (PDF) and the paper Henrick Hellström mentioned in his ...

Feb 10, 2021 · However, the story is not finished There: In 2006, Jongsung Kim, Alex Biryukov, Bart Preneel, and Seokhie Hong showed that they can distinguish HMAC if instantiated with reduced versions of MD5 and SHA-1 or instantiated full versions of HAVAL, MD4, and SHA-0 from a random function or HMAC with a random function.