AEZ: Anything-But EaZy in Hardware

Abstract

We provide the first hardware implementation of AEZ, a third-round candidate to the CAESAR competition for authenticated encryption. Complex, optimized for software, and impossible to implement in a single pass, AEZ poses significant obstacles for any hardware realization. Still, we find that a hardware implementation of AEZ is quite feasible. On Xilinx Virtex-6 FPGAs, our single-core design has a throughput exceeding 3.4 Gbit/s, and uses about 4600 LUTs and about 1250 CLB slices. In terms of the throughput to area ratio, this performance places it on the 12th position among 28 CAESAR candidate families benchmarked during Round 2 of the competition (assuming the key size of at least 96 bits, and the limit on the message size equal to $2^{11}-1$ bytes). At the same time, AEZ targets a stronger notion of security against the cipher misuse than all other algorithms implemented and ranked ahead of it in the Round 2 hardware benchmarking study.