## Cryptology ePrint Archive: Report 2020/509

BBB Secure Nonce Based MAC Using Public Permutations

Avijit Dutta and Mridul Nandi

Abstract: In the recent trend of CAESAR competition and NIST light-weight competition, cryptographic community have witnessed the submissions of several cryptographic schemes that are build on public random permutations. Recently, in CRYPTO 2019, Chen et al. have initiated an interesting research direction in designing beyond birthday bound PRFs from public random permutations and they proposed two instances of such PRFs. In this work, we extend this research direction by proposing a nonce-based MAC build from public random permutations. We show that our proposed MAC achieves $2n/3$ bit security (with respect to the state size of the permutation) and the bound is essentially tight. Moreover, the security of the MAC degrades gracefully with the repetition of the nonce.

Category / Keywords: secret-key cryptography / Faulty Nonce, Mirror Theory, Public Permutation, Expectation Method

Original Publication (in the same form): AFRICACRYPT 2020