Clock-controlled generators with large period output sequences

摘要

Clock-controlled generators are a kind of pseudo-random number generators (PRNG). Recently, some clock-controlled generators based on jumping Linear Finite State Machines (LFSMs) have been proposed, such as Pomaranch and MICKEY. The period and the linear complexity of their output sequences need to be large enough to provide security against linear attacks. In this paper, a new condition for the period to reach its maximal value is presented. The condition is better than the previous one. Further, some clock-controlled generators are considered, including a new generator which uses a Feedback with Carry Shift Register (FCSR) as the control register. How to maximise the period of their output sequences is investigated.