## Cryptology ePrint Archive: Report 2003/139

On the Randomness of the Editing Generator

Enjian Bai and Guozhen Xiao

Abstract: In their paper, G.Gong and S.Q.Jiang construct a new pseudo-random sequence generator by using two ternary linear feedback shift registers (LFSR). The new generator is called an editing generator which a combined model of the clock-controlled generator and the shrinking generator. For a special case (Both the base sequence and the control sequence are mm-sequence of degree $n$), the period, linear complexity, symbol distribution and security analysis are discussed in the same article. In this paper, we expand the randomness results of the edited sequence for general cases, we do not restrict the base sequence and the control sequence has the same length. For four special cases of this generator, the randomness of the edited sequence is discussed in detail. It is shown that for all four cases the editing generator has good properties, such as large periods, high linear complexities, large ratio of linear complexity per symbol, and small un-bias of occurrences of symbol. All these properties make it a suitable crypto-generator for stream cipher applications.

Category / Keywords: secret-key cryptography / Stream ciphers, Pseudo-random sequences, Clock-controlled generator, Shrinking generator