Preimage Attack on MD4 Hash Function as a Problem of Parallel Sat-Based Cryptanalysis

In this paper we study the inversion problem of MD4 cryptographic hash function developed by R. Rivest in 1990. By MD4-k we denote a truncated variant of MD4 hash function in which k represents a number of steps used to calculate a hash value (the full version of MD4 function corresponds to MD4-48). H. Dobbertin has showed that MD4-32 hash function is not one-way, namely, it can be inverted for the given image of a random input. He suggested to add special conditions to the equations that describe the computation of concrete steps (chaining variables) of the considered hash function. These additional conditions allowed to solve the inversion problem of MD4-32 within a reasonable time by solving corresponding system of equations. The main result of the present paper is an automatic derivation of “Dobbertin’s conditions” using parallel SAT solving algorithms. We also managed to solve several inversion problems of functions of the kind MD4-k (for k from 31 up to 39 inclusive). Our method significantly outperforms previously existing approaches to solving these problems

Protect data from attacking by authenticate clients using Kerberos protocol

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Пропозиції з реалізації системи цифрових підписів в Україні

Розглядається варіант побудови системи цифрового підпису на основі інфраструктури відкритих ключів з використанням електронних паспортів.In the paper the variant of construction of system of the digital signature is considered on the basis of an infrastructure of open keys with use the virtual passports

Detecting changes in environment of mobile robot

The usefulness of four signature schemes for detecting changes in environment of mobile robot is investigated. Computational and memory complexities of software implementations of the schemes are experimentally compared. Finally, the best of the schemes for considered application is chosen

Linear and Differential Cryptanalysis of SHA-256

The one-way hash function plays an important role in digital signatures and message authentication from the viewpoint of security. No effective attacking method has been discovered to the algorithm of hash function standard. In this study, we tried to attack SHA-256 in encryption mode using linear and differential cryptanalysis to solve a private key. We deduced that an estimate of the private key would require huge known and chosen plaintexts in both linear and differential cryptanalysis, and that it would be difficult to decipher SHA-256 in view of the required computation

Performance Calculation of Hash Sha-1 in Embedded System Using Arduino

The development of digital electronic devices that can communicate with each other causing the need for data security or data protection. However, in the many digital electronic devices are not equipped with security or protection of the data. In this study has the main objective to design an embedded system that can be added to the digital electronic devices to provide security or protection of the data. As the initial phase of the study, in this paper have measured performance data security in embedded systems with Arduino using a cryptographic algorithm SHA-1 hash function. Performance of SHA-1 hash calculation using linear regression approach of measurement results show for 1 byte of data takes time 2,505 ms. Each additional 1 byte of data calculation time hash function SHA-1 increased 0.0715 ms

Проблеми і тенденції розвитку апаратних засобів захисту інформації

Розглядаються сучасні апаратні засоби реалізації криптографічних алгоритмів, криптографічних функцій та криптографічних протоколів, їх параметри та напрямки розвитку.Нardware for realization of modern cryptographic algorithms, functions and protocols, their parameters and development directions are considered in the paper