Collision attack

About: Collision attack is a research topic. Over the lifetime, 1093 publications have been published within this topic receiving 28389 citations.

Efficient parallelizable hashing using small non-compressing primitives

Abstract: A well-established method of constructing hash functions is to base them on non-compressing primitives, such as one-way functions or permutations. In this work, we present $$S^r$$Sr, an $$rn$$rn-to-$$n$$n-bit compression function (for $$r\ge 1$$r?1) making $$2r-1$$2r-1 calls to $$n$$n-to-$$n$$n-bit primitives (random functions or permutations). $$S^r$$Sr compresses its inputs at a rate (the amount of message blocks per primitive call) up to almost 1/2, and it outperforms all existing schemes with respect to rate and/or the size of underlying primitives. For instance, instantiated with the $$1600$$1600-bit permutation of NIST's SHA-3 hash function standard, it offers about $$800$$800-bit security at a rate of almost 1/2, while SHA-3-512 itself achieves only $$512$$512-bit security at a rate of about $$1/3$$1/3. We prove that $$S^r$$Sr achieves asymptotically optimal collision security against semi-adaptive adversaries up to almost $$2^{n/2}$$2n/2 queries and that it can be made preimage secure up to $$2^n$$2n queries using a simple tweak.

An Improved Collision Attack on MD5 Algorithm

Abstract: The research on the attack algorithm for a MD5 collision is one of the focuses in cryptology nowadays. In this paper, by analyzing the properties of the nonlinear Boolean functions used in MD5 and the differences in term of XOR and subtraction modulo 232, we prove that some sufficient conditions presented by Jie Liang and Xuejia Lai are also necessary to guarantee the differential path and give a set of necessary and sufficient conditions to guarantee the output differences of the last two steps. Then we present an improved collision attack algorithm on MD5 by using the set of necessary and sufficient conditions. Finally, we analyze the computational complexity of our attack algorithm which is 0.718692 times of that of the previous collision attack algorithms.

Internal collision attack on Maraca

Abstract: We present an internal collision attack against the new hash function Maraca which has been submitted to the SHA-3 competition. This attack requires 2^{237} calls to the round function and its complexity is lower than the complexity of the generic collision attack when the length of the message digest is greater than or equal to 512. It is shown that this cryptanalysis mainly exploits some particular differential properties of the inner permutation, which are in some sense in contradiction with the usual security criterion which guarantees the resistance to differential attacks.

Attacks Against Permute-Transform-Xor Compression Functions and Spectral Hash.

Abstract: This paper presents an attack on the strong collision resistance of the Spectral Hash SHA-3 candidate. Spectral-Hash (shash) is a Merkle-Damg ard based hash function, carefully designed to resist all known cryptographic attacks. To best of our knowledge, our attack is the only known attack against the shash algorithm. We exploit the fundamental structure of the algorithm, completely bypassing the hash function’s formidable cryptographic protections. Our attack is presented in three stages. First, we dene the family of functions which have the structure we wish to exploit. We call members of this family PTX functions. Next, we show that all PTX functions, including functions which use random oracles, are vulnerable to our collision attack. Finally, we reformulate the shash compression function showing that it is a PTX function and thus vulnerable. We present results on a practical implementation of our attack, generating collisions for shash in less than a second on a typical desktop computer. r r r r b b b b b b b b b b b b r r r r