Cryptology ePrint Archive: Report 2013/398

ASICS: Authenticated Key Exchange Security Incorporating Certification Systems

Colin Boyd and Cas Cremers and Michèle Feltz and Kenneth G. Paterson and Bertram Poettering and Douglas Stebila

Abstract: Most security models for authenticated key exchange (AKE) do not explicitly model the associated certification system, which includes the certification authority (CA) and its behaviour. However, there are several well-known and realistic attacks on AKE protocols which exploit various forms of malicious key registration and which therefore lie outside the scope of these models. We provide the first systematic analysis of AKE security incorporating certification systems (ASICS). We define a family of security models that, in addition to allowing different sets of standard AKE adversary queries, also permit the adversary to register arbitrary bitstrings as keys. For this model family we prove generic results that enable the design and verification of protocols that achieve security even if some keys have been produced maliciously. Our approach is applicable to a wide range of models and protocols; as a concrete illustration of its power, we apply it to the CMQV protocol in the natural strengthening of the eCK model to the ASICS setting.

Category / Keywords: cryptographic protocols / authenticated key exchange (AKE), unknown key share (UKS) attacks, certification authority (CA), invalid public keys, PKI

Publication Info: Full version of the ESORICS 2013 paper

Date: received 18 Jun 2013

Contact author: feltzm at inf ethz ch

Available format(s): PDF | BibTeX Citation

Version: 20130618:092001 (All versions of this report)

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