Protecting the NOEKEON Cipher against SCARE Attacks in FPGAs by Using Dynamic Implementations

Protecting an implementation against side channel analysis for reverse engineering (SCARE) attacks is a great challenge and we address this challenge by presenting a first proof of concept. White-box cryptography has been developed to protect programs against an adversary who has full access to their software implementation. It has also been suggested as a countermeasure against side channel attacks and we examine here these techniques in the wider perspective of SCARE. We consider that the adversary has only access to the cryptographic device through its side channels and his goal is to recover the specifications of the algorithm. In this work, we focus on FPGA (field-programmable gate array) technologies and examine how to thwart SCARE attacks by implementing a block cipher following white-box techniques. The proposed principle is based on changing dynamically the implementations. It is illustrated by an example on the Noekeon cipher and feasibility in different FPGAs is studied.