A stream cipher based on linear feedback over GF(28)

Abstract

Embedded applications such as voice encryption in wireless telephones can place severe constraints on the amount of processing power, program space and memory available for software encryption algorithms. Additionally, some protocols require some form of two-level keying which must be reasonably fast. This paper introduces a mechanism for creating a family of stream ciphers based on Linear Feedback Shift Registers over the Galois Finite Field of order 2n, where n is chosen to be convenient for software implementation. A particular stream cipher based on this methodology, SOBER, is presented and analysed.