Orthogonal Direct Sum Masking: A Smartcard Friendly Computation Paradigm in a Code, with Builtin Protection against Side-Channel and Fault Attacks.
Julien Bringer, Claude Carlet, Hervé Chabanne, Sylvain Guilley, Houssem Maghrebi · 2014
Abstract. Secure elements, such as smartcards or trusted platform mod-ules (TPMs), must be protected against implementation-level attacks. Those include side-channel and fault injection attacks. We introduce ODSM, Orthogonal Direct Sum Masking, a new computation paradigm that achieves protection against those two kinds of attacks. A large vec-tor space is structured as two supplementary orthogonal subspaces. One subspace (called a code C) is used for the functional computation, while the second subspace carries random numbers. As the random numbers are entangled with the sensitive data, ODSM ensures a protection against (monovariate) side-channel attacks. The random numbers can be checked either occasionally, or globally, thereby ensuring a fine or coarse detec-tion capability. The security level can be formally detailed: it is proved that monovariate side-channel attacks of order up to dC − 1, where dC is the minimal distance of C, are impossible, and that any fault of Ham-ming weight strictly less than dC is detected. A complete instantiation of ODSM is given for AES. In this case, all monovariate side-channel at-tacks of order strictly less than 5 are impossible, and all fault injections perturbing strictly less than 5 bits are detected.