SHA_1 Enhancement Based on Resilent Boolean Function

Abstract

SHA_1 is a one way hash function which is used in cryptographic systems to provide message authentication and integrity. In recent year this algorithm faced new type of attacks. These attacks make use of the simplicity of message expansion step to leak some information used to build a matching patterns or build differential path according to local collision. In this paper an enhanced version of SHA_1 was proposed depend on using resilent Boolean function which is a Boolean function that offers properties of balancedness, algebraic degree, correlation immunity and nonlinearity. This enhancement tends to countermeasures these attacks. Enhancement was made in two places for the original algorithm, first enhanced message expansion process, second change the value of 32 variable inputs to Boolean function in the algorithm.