Smart cards are vulnerable to both invasive and non-invasive attacks. Specifically, non-invasive attacks using power and timing measurements to extract the cryptographic key has drawn a lot of negative publicity for smart card usage. The power measurement techniques rely on the data-dependent energy behavior of the underlying system. Further, power analysis can be used to identify the specific portions of the program being executed to induce timing glitches that may in turn help to bypass key checking. Thus, it is important to mask the energy consumption when executing the encryption algorithms. In this work, we augment the instruction set architecture of a simple five-stage pipelined smart card processor with secure instructions to mask the energy differences due to key-related datadependent computations in DES encryption. The secure versions operate on the normal and complementary versions of the operands simultaneously to mask the energy variations due to value dependent operations...
Hendra Saputra, Narayanan Vijaykrishnan, Mahmut T.