Towards Optimally Efficient Secret-Key Authentication from PRG.
Ivan Damgård, Sunoo Park · IACR Cryptology ePrint Archive · 2014
We propose a new approach to the construction of secret-key authentication protocols making black-box use of any pseudorandom generator (PRG). Our authentication protocols require only two messages, have perfect completeness, and achieve concurrent man-in-the-middle security. Finally, when based on a sufficiently efficient PRG, our protocol has (amortised) complexity O(n) bit operations where n is the security parameter. To the best of our knowledge, this construction is the first with linear complexity. We achieve this at the cost of having the prover (but not the verifier) keep a small amount of state. A variant of our construction, based on a stronger security notion for the PRG, is secure even if the adversary is able to reset the prover an unbounded number of times. A practical analysis of our protocol shows our prover computation time compares favorably against a simple AES-based protocol.