Paper 2014/264

Continuous After-the-fact Leakage-Resilient Key Exchange (full version)

Janaka Alawatugoda, Colin Boyd, and Douglas Stebila


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.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. MINOR revision.The 19th Australasian Conference on Information Security and Privacy (ACISP 2014)
leakage resiliencekey exchangecontinuous leakageafter-the-factsecurity models
Contact author(s)
janaka alawatugoda @ qut edu au
2015-05-01: revised
2014-04-20: received
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Creative Commons Attribution


      author = {Janaka Alawatugoda and Colin Boyd and Douglas Stebila},
      title = {Continuous After-the-fact Leakage-Resilient Key Exchange (full version)},
      howpublished = {Cryptology ePrint Archive, Paper 2014/264},
      year = {2014},
      note = {\url{}},
      url = {}
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