On Searching Dynamic Feedback with Carry Shift Registers Having Sparse Switches
Sen Hou, Yue Cao · 2023
A bitstring generator is proposed by transferring from one feedback with carry shift register (FCSR) to another under control of an (external) signal, and it is called a dynamic feedback with carry shift register (DFCSR). Cryptographic applications require that the period of sequences generated by each FCSR of a DFCSR should be as large as possible, and for optimal performance the number of switches transferring FCSRs should be as least as possible. In this correspondence a probabilistic algorithm is given to find such required DFCSRs. By theoretical estimation and heuristic experiments, this searching technique is shown to be practically feasible for contemporary cryptographic sizes.