A double length hash function is a 2n-bit hash function based on an n-bit compression function. To increase the security level, designs of good double length hash functions are important. In this paper we construct a class of maximally secure double length hash functions in random oracle model based on some good permutations. This class contains recently proposed double length hash functions [1...

Lately, hash function security has received increased attention. Especially after the recent attacks that were presented for SHA-1 and MD5, the need for a new and more robust hash function has become imperative. Even though many solutions have been proposed as replacements, the transition to a new function could be costly and complex. In this paper, we introduce a mode of operation that can be ...

In Cryptography, hash functions play a fundamental role in mapping messages into hash codes, where hash codes are served as compact representative of input messages. The hash function is a many-to-one function. Same hash function can be generated from different input messages, implying that the existence of collisions. Cryptographic hash functions are used for data integrity in conjunction with...

An important property of a hash function is the performance. We study fast iterated hash functions based on block ciphers. These hash functions and their compression functions are analyzed in the standard black-box model. We show an upper bound on rate of any collision resistant hash function. In addition, we improve known bound on the rate of collision resistant compression functions.

Hash functions are inseparable part of modern computer world. Fast associative arrays so popular among computer programmers for their robustness and simplicity, are based on them. Their performance greatly depends on their design and although their roots are deep in the past, the topic of designing a well performing hash function is still often discussed today. There is currently a plenty of ex...

In recent years there have been a series of serious and alarming cryptanalytic attacks on several commonly-used hash functions, such as MD4, MD5, SHA-0, and SHA1 [13, 38]. These culminated with the celebrated work of Wang, Yin, and Yu from 2005, which demonstrated relatively efficient methods for finding collisions in the SHA-1 hash function [37]. Although there are several cryptographic hash f...

This paper describes a new software-efficient 256-bit hash function, FORK-256. Recently proposed attacks on MD5 and SHA-1 motivate a new hash function design. It is designed not only to have higher security but also to be faster than SHA-256. The performance of the new hash function is at least 30% better than that of SHA-256 in software. And it is secure against any known cryptographic attacks...

In a recent paper, Lucks espoused a “failure-friendly” approach to hash function design [12]. We expand on this idea in two main ways. First of all, we consider the notion of a weak ideal compression function, which is vulnerable to strong forms of attack, but is otherwise random. We show that such weak ideal compression functions can be used to create secure hash functions, thereby giving a de...

In this paper, the author studies the fast cryptographic hash function. This work suggests a different notion with respect to the traditional hash functions, MD5, SHA-1, and Whirlpool. The notion of block cipher based hash function is abandoned. According to the flexibility of attack, it shows how this hash function is no longer vulnerable to the known collision attacks. Finally, the author pro...

In a recent paper in crypto-04, A. Joux [6] showed a multicollision attacks on the classical iterated hash function. He also showed how the multicollision attack can be used to get a collision attack on the concatenated hash function. In this paper we have shown that the multicollision attacks exist in a general class of sequential or tree based hash functions even if message blocks are used tw...