INCREASING THE RATE OF OUTPUT OF M-SEQUENCES

Maximal length Linear Shift Register sequences (m-sequences) are widely used in digital systems, such as stream ciphers, which require fast, easily produced bitstreams with good statistical properties. Since many applications require rapid generation of m-sequences, it is desirable to study methods of increasing their rate of output. M. Robshaw (1991) showed how to interleave the outputs of 2i primitive LFSRs in order to produce an m-sequence at an increased rate. We use a generalisation of this technique, enabling k m-sequences to be interleaved where k is coprime to the period of the m-sequence, to show that in some situations less than k registers are needed to generate an m-sequence at k times the rate of the individual registers.