Most present symmetric encryption algorithms result from a tradeoff between implementation cost and resulting performances. In addition, they generally aim to be implemented efficiently on a large variety of platforms. In this paper, we take an opposite approach and consider a context where we have very limited processing resources and throughput requirements. For this purpose, we propose low-cost encryption routines (i.e. with small code size and memory) targeted for processors with a limited instruction set (i.e. AND, OR, XOR gates, word rotation and modular addition). The proposed design is parametric in the text, key and processor size, allows efficient combination of encryption/decryption, "on-the-fly" key derivation and its security against a number of recent cryptanalytic techniques is discussed. Target applications for such routines include any context requiring low-cost encryption and/or authentication.
['François-Xavier Standaert', 'Jean-Jacques Quisquater', 'Gilles Piret', 'Neil Gershenfeld']
SEA: A scalable encryption algorithm for small embedded applications