Pseudo-Random Number Generation Applied to Robust Modern Cryptography: A New Technique for Block Ciphers

Latest mitigation techniques proposed at registers transfer level for dependable cryptosystems deal with time redundancy in an active on-line error-detection scheme. Round-based block ciphers are very likely to be hardened with these techniques. Although good results are achieved in terms of area or time overhead, intentional attacks are still able to obtain crucial information by means of intensive fault injection campaigns. In this paper, a new solution is presented and analyzed, dealing with pseudo-random number generators (PRNG) with the goal of misleading attackers and, therefore, making cryptosystem more robust. With this approach, attackers must face two difficulties: dealing with on-line error detection and ignoring the fault location in the round sequence. PRNG will produce different repetition sequences for the rounds of the cryptosystem, making very difficult to correlate output data with injected faults.