Provably Secure Masking of AES

A general method to secure cryptographic algorithm implementations against side-channel attacks is the use of randomization techniques and, in particular, masking. Roughly speaking, using random values unknown to an adversary one masks the input to a cryptographic algorithm. As a result, the intermediate results in the algorithm computation are uncorrelated to the input and the adversary cannot obtain any useful information from the side-channel. Unfortunately, previous AES randomization techniques have based their security on heuristics and experiments. Thus, flaws have been found which make AES randomized implementations still vulnerable to side-channel cryptanalysis. In this paper, we provide a formal notion of security for randomized maskings of arbitrary cryptographic algorithms. Furthermore, we present an AES randomization technique that is provably secure against side-channel attacks if the adversary is able to access a single intermediate result. Our randomized masking techniq...

• Type: Conference
• Year: 2004
• Where: SACRYPT
• Authors: Johannes Blömer, Jorge Guajardo, Volker Krummel
• Keywords: Cryptographic Algorithms, Randomization Technique, SACRYPT 2004, Side-channel Attacks