Secure Implementation of Stream Cipher: Trivium

Trivium is a hardware oriented synchronous stream cipher designed by Christophe De Canniere and Bart Preneel [7]. Trivium is one of the eSTREAM final portfolio cipher. Regardless of the security of the cipher in theory, implementation attacks like Differential Power Analysis (DPA) attack [10,12,18] and Fault attack [9] on Trivium were observed. DPA attack of Trivium exploits the re-synchronization phase of the algorithm to reveal the key. In this paper, we analyse various implementation techniques as countermeasures for Trivium stream cipher against DPA attack. First, we present Threshold Implementation (TI) of Trivium using random mask value. Second, we propose algorithm level changes (Modified Trivium) to counteract the attack, which introduces negligible resource overhead to the implementation. Third, random accelerator concept is introduced for parallel architecture along with combined techniques of TI and algorithm level changes to further increase the attack complexity. Finally, we present comparative study on the performance of Trivium for the proposed techniques.