LT code design based on RC4 sequential cipher

Abstract

As the first practical fountain code, LT (Luby Transform) code is the basis of other fountain codes. In theory, for each encoding symbol of LT code, the neighbors used to generate that encoding symbol are chosen uniformly at random. Practical implementations of LT codes usually realize the randomness through pseudo-randomness number generators like LCG (Linear Congruential Generator). In this paper, an LT code design based on RC4 sequential cipher is proposed, which we called RC4-LT code. In RC4-LT code, the traditional linear congruential method is replaced with RC4 sequential cipher to generate random number stream, and a scrambling degree neighbor generation algorithm is proposed. Moreover, we exploit the cryptographic properties of RC4 algorithm to implement secure data transmission. Simulation results show that, RC4-LT code has more efficient decoding performance, smaller transmission overhead and necessary security compared with the conventional LT code.