X-FCSR - A New Software Oriented Stream Cipher Based Upon FCSRs

Abstract. Feedback with Carry Shift Registers (FCSRs) are a promising alternative to LFSRs in the design of stream ciphers. The previous constructions based on FCSRs were dedicated to hardware applications [3]. In this paper, we will describe X-FCSR a family of software oriented stream ciphers using FCSRs. The core of the system is composed of two 256-bits FCSRs. We propose two versions: X-FCSR-128 and X-FCSR256 which output respectively 128 and 256 bits at each iteration. We study the resistance of our design against several cryptanalyses. These stream ciphers achieve a high throughput and are suitable for software applications (6.3 cycles/byte).

• Type: Conference
• Year: 2007
• Where: INDOCRYPT
• Authors: François Arnault, Thierry P. Berger, Cédric Lauradoux, Marine Minier
• Keywords: Carry Shift Registers, INDOCRYPT 2007, Software Oriented Stream, Stream Ciphers