Janaka Alawatugoda

Continuous After-the-Fact Leakage-Resilient Key Exchange

Security models for two-party authenticated key exchange (AKE) protocols have developed over time to provide security even when the adversary learns certain secret keys. In this work, we advance the modelling of AKE protocols by considering more granular, continuous leakage of long-term secrets of protocol participants: the adversary can adaptively request arbitrary leakage of long-term secrets even after the test session is activated, with limits on the amount of leakage per query but no bounds on the total leakage. We present a security model supporting continuous leakage even when the adversary learns certain ephemeral secrets or session keys, and give a generic construction of a two-pass leakage-resilient key exchange protocol that is secure in the model; our protocol achieves continuous, after-the-fact leakage resilience with not much more cost than a previous protocol with only bounded, non-after-the-fact leakage.

Continuous After-the-Fact Leakage-Resilient eCK-Secure Key Exchange

Security models for two-party authenticated key exchange AKE protocols have developed over time to capture the security of AKE protocols even when the adversary learns certain secret values. Increased granularity of security can be modelled by considering partial leakage of secrets in the manner of models for leakage-resilient cryptography, designed to capture side-channel attacks. In this work, we use the strongest known partial-leakage-based security model for key exchange protocols, namely continuous after-the-fact leakage

Software implementation level countermeasures against the cache timing attack on advanced encryption standard

\mathrm {eCK}

On the leakage-resilient key exchange

\mathrm {CAFL\text {-}eCK}

Continuous after-the-fact leakage-resilient eCK-secure key exchange

model. We resolve an open problem by constructing the first concrete two-pass leakage-resilient key exchange protocol that is secure in the