The paper discusses the security of compression function and hash function with Merkle-Damg̊ard construction and provides the complexity bound of finding a collision and primage of hash function based on the condition probability of compression function y = F (x, k). we make a conclusion that in Merkle-Dammåard construction, the requirement of free start collision resistant and free start collis...

We developed minimal perfect hash functions for a variety of datasets using the probabilistic process of simulated annealing (SA). The SA solution structure is a tree representing an annealed program (algorithm). This solution structure is similar to the structure used in genetic programming. When executed, the SA program produces multiple hash functions for the given data set. An initial hash ...

A signature scheme constructed according to the hash-andsign paradigm—hash the message and then sign the hash, symbolically σ(H(M))—is no more secure than the hash function H against a collision-finding attack. Recent attacks on standard hash functions call the paradigm into question. It is well known that a simple modification of the hash-and-sign paradigm may replace the collision-resistant h...

We study some properties of the Cayley graph of the R.Thompson’s group F in generators x0, x1. We show that the density of this graph, that is, the least upper bound of the average vertex degree of its finite subgraphs is at least 3. It is known that a 2generated group is not amenable if and only if the density of the corresponding Cayley graph is strictly less than 4. It is well known this is ...

We consider a simple and secure way to realize a synchronous stream cipher from iterated hash functions. It is similar to the OFB mode where the underlying block cipher algorithm is replaced with the keyed hash function, adopting the secret suffix method[20]. We analyzed the key, the keystream and the necessary properties to assume from the underlying hash function for the stream cipher to be c...

In this paper a new hash function is constructed based on multilayer feed forward network with piecewise linear chaotic map. Chaos has been used in data protection because of the features of initial value sensitivity, random similarity and ergodicity. We have used three neuronal layers to prove confusion, diffusion and compression respectively. This hash function takes input of arbitrary length...

The most common way of constructing a hash function (e.g., SHA-1) is to iterate a compression function on the input message. The compression function is usually designed from scratch or made out of a block-cipher. In this paper, we introduce a new security notion for hash-functions, stronger than collision-resistance. Under this notion, the arbitrary length hash function H must behave as a rand...

One way hash functions are an important tool in achieving authentication and data integrity The aim of this paper is to propose a novel one way hash function based on cellular automata whose cryp tographic properties have been extensively studied over the past decade or so Furthermore security of the proposed one way hash function is analyzed by the use of very recently published results on app...

We prove that there are no black-box reductions from Collision-Free Hash Functions to secure time-stamping schemes, which means that in principle secure time-stamping schemes may exist even if there exist no collision-resistant hash functions. We show that there is an oracle relative to which there exist secure time-stamping schemes but no hash function is collision-free. The oracle we use is n...

Biham and Chen proposed an attack on SHA-0 at Crypt 2004. In this paper, we apply the Biham-Chen attack to analyze SHAlike hash functions regarding pseudo-collision resistance and pseudorandomness. We present a scenario about how to attack SHA-like hash functions applying the Biham and Chen attack. Using this scenario, we present a differential attack on the MD5 hash function and a differential...