Efficient Leakage-Resilient Authenticated Key Agreement Protocol in the Continual Leakage eCK Model

Based on users' permanent private keys and ephemeral secret keys (randomness secret values), authenticated key agreement (AKA) protocols are used to construct a common session key between two session parties while authenticating each other. Recently, the design of leakage-resilient AKA (LR-AKA) resisting side-channel attacks has received significant attention from researchers. By side-channel attacks, an adversary is allowed to obtain fractional leakage information of private (secret) keys during the computation rounds of LR-AKA protocols. However, most LR-AKA protocols have a restriction, namely, the overall fractional leakage information must be bounded. In this paper, we propose an efficient LR-AKA protocol with overall unbounded leakage property in the continual leakage extended Canetti-Krawczyk model. Security analysis is given to demonstrate that our LR-AKA protocol is provably secure in the generic bilinear group model. By comparisons, our protocol is better than the previously proposed LR-AKA protocols in terms of computation cost, security model, and leakage properties.