DEVELOPMENT OF RC4 STREAM CIPHERS USING BOOLEAN FUNCTIONS

Abstract

RC4 was designed by Ron Rivest in 1987 as an attempt to make a stream cipher which is more suitable for software implementations. He did not use Linear Feed Back Shift Register (LFSR) at all, but used a dynamic permutation instead. RC4 is one of the most popular stream ciphers and widely used in practical software applications. The paper describes the functioning of RC4 and present previously published analysis and present a new modified cipher algorithm which uses a similar internal organization to RC4, but uses different methods. The proposed variation of RC4 increase the performance of the implementation of the RC4, two secret key arrays and two lock up table to maximize the size of the random sequence size, were used. The proposed system offers more randomness in the sequences; also, the maximum length of the sequence is appeared longer than the origin RC4 that makes the cryptanalysis more complex than RC4.