Friet: An Authenticated Encryption Scheme with Built-in Fault Detection

In this work we present a duplex-based authenticated encryption scheme Friet based on a new permutation called Friet-P. We designed Friet-P with a novel approach for cryptographic permutations and block ciphers that takes fault-attack resistance into account and that we introduce in this paper.

In this method, we build a permutation fC to be embedded in a larger one, f . First, we define f as a sequence of steps that all abide a chosen error-correcting code C, i.e., that map C-codewords to C-codewords. Then, we embed fC in f by first encoding its input to an element of C, applying f and then decoding back from C. This last step detects a fault when the output of f is not in C.

We motivate the design of the permutation we use in Friet and report on performance in soft-and hardware. We evaluate the faultdetection capabilities of the software and simulated hardware implementations with attacks. Finally, we perform a leakage evaluation. Our code is available at https://github.com/thisimon/Friet.git.