Section: New Results

Improvements on CBC MAC formalized in EasyCrypt

Participants : Benjamin Grégoire, Cécile Baritel-Ruet, Pierre-Alain Fouque.

In a paper of 2003, J. Black and P. Rogaway propose variations of cipher block chaining message authentication codes for the efficient authentication of arbitrary length messages. We formalize their work in EasyCrypt, resulting in formal proofs for CBC-MAC, EMAC, ECBC, FCBC and the most efficient of these variations, XCBC.

This work required the development of new EasyCrypt theories. A small flaw in the original paper was found and a fix has been proposed. This work was partially funded by the Brutus ANR project.