From New Technologies to New Solutions - Exploiting FRAM Memories to Enhance Physical Security.

Ferroelectric RAM (FRAM) is a promising non-volatile memory technology that is now available in low-end microcontrollers. Its main advantages over Flash memories are faster write performances and much larger tolerated number of write/erase cycles. These properties are profitable for the efficient implementation of side-channel countermeasures exploiting pre-computations. In this paper, we illustrate the interest of FRAM-based microcontrollers for physically secure cryptographic hardware with two case studies. First we consider a recent shuffling scheme for the AES algorithm, exploiting randomized program memories. We exhibit significant performance gains over previous results in an Atmel microcontroller, thanks to the fine-grained programmability of FRAM. Next and most importantly, we propose the first working implementation of the “masking with randomized look-up table” countermeasure, applied to reduced versions of the block cipher LED. This implementation provides unconditional security against side-channel attacks ( of all orders! ) under the assumption that pre-computations can be performed without leakage. It also provides high security levels in cases where this assumption is relaxed (e.g. for context or performance reasons).