Pseudo-random sequence generators with improved inviolability performance

Abstract

A novel stream cipher based on the popular linear feedback shift register (LFSR) with a dynamic feedback network controlled by a decoder circuit is presented. The proposed circuit can be employed efficiently in cryptographic applications owing to its improved inviolability property compared to traditional LFSRs. Indeed, although the proposed topology and traditional LFSRs have similar statistical properties, it exhibits a very high linear complexity (LC) and the sequences generated from the novel topology are much more difficult to be predicted. The proposed cipher is described and design criteria to choose the key of the system are also given. As an example, a 16-bit length generator was implemented on a Xilinx FPGA and experimentally verified using the most common statistical and randomness tests. Then it was also designed in standard cell AMS technology. Moreover, to test the generator's inviolability, a novel methodology, based on a multi-perceptron neural network, was also developed and is also presented.