Leakage Resilient ElGamal Encryption

Blinding is a popular and well-known countermeasure to protect public-key cryptosystems against side-channel attacks. The high level idea is to randomize an exponentiation in order to prevent multiple measurements of the same operation on different data, as such measurements might allow the adversary to learn the secret exponent. Several variants of blinding have been proposed in the literature, using additive or multiplicative secret-sharing to blind either the base or the exponent. These countermeasures usually aim at preventing particular side-channel attacks (mostly power analysis) and come without any formal security guarantee. In this work we investigate to which extend blinding can provide provable security against a general class of side-channel attacks. Surprisingly, it turns out that in the context of public-key encryption some blinding techniques are more suited than others. In particular, we consider a multiplicatively blinded version of ElGamal public-key encryption where

• Type: Journal
• Year: 2010
• Where: ASIACRYPT
• Authors: Eike Kiltz, Krzysztof Pietrzak
• Keywords: ASIACRYPT 2010, Continuous Leakage, Cryptology, Public-key Encryption, Side-channel Attacks