An approach to assess the optimality of refining RC4

摘要

Though RC4 has proved itself as a simple, fast and robust stream cipher and it is trusted by many organizations, a number of researchers claimed that RC4 has some weakness and bias in its internal states. To increase its security, some guidelines recommended discarding some initial bytes like N, 2N or more from the RC4 key-stream (N is 256, generally). In this paper, the authors tried to find out the optimum number of bytes that is to be discarded to have a more secured RC4, by analyzing some variants of it. All the algorithms, including the original one, are analyzed by the NIST Statistical Test Suite and it has been found that it is not necessary discarding more and more number of bytes to increase the security of RC4.