Mixed Techniques to Protect Precharged Busses against Differential Power Analysis Attacks

In this paper, techniques to improve the resistance against differential power analysis (DPA) attacks of precharged busses in cryptographic circuits are discussed. In particular, two techniques that were previously introduced by the same authors are properly mixed to further enhance the immunity to DPA attacks. The achieved robustness against DPA attacks is shown to be considerably improved, compared with the case of a separate adoption of each technique. Criteria to manage the security-power-area trade-off are also derived from a statistical analysis of precharged busses. The mixed technique is finally validated by means of both cycle-accurate and circuit simulations on the DES encryption algorithm running on a MIPS32 architecture.