MRMM-Based Keystream Generators for Information Security

The central theme of a stream cipher is a keystream generator that produces a pseudorandom bit sequence and is popularly used to ensure privacy over a communication channel. The word-based linear feedback shift register also known as the multiple recursive matrix method (MRMM) is attractive as it possesses most of the randomness properties like linear feedback shift register. It also takes advantage of modern word-based processors and thus increases the throughput. The major drawback of MRMM is that it has low linear complexity. In order to address the low linear complexity drawback in MRMM, the concept of several bit-oriented generators is extended to MRMMs. For this, a generalized form of the feedback function for word-oriented feedback shift registers is discussed, and then study MRMM as a special case.