Improved Cryptanalysis of the Common Scrambling Algorithm Stream Cipher

摘要: This paper provides a fresh analysis of the widely-used Common Scrambling Algorithm stream cipher (CSA-SC). Firstly, new representation CSA-SC with state size only 89 bits is given, significant reduction from 103 bit previous representation. Analysis this 89-bit demonstrates that basis guess-and-determine attack flawed. Correcting flaw increases complexity so it worse than exhaustive key search. Although not feasible, reduced our makes obvious vulnerable to several generic attacks, for which feasible parameters are given.