Cryptology ePrint Archive: Report 2017/559

Human Computing for Handling Strong Corruptions in Authenticated Key Exchange

Alexandra Boldyreva and Shan Chen and Pierre-Alain Dupont and David Pointcheval

Abstract: We propose the first user authentication and key exchange protocols that can tolerate strong corruptions on the client-side. If a user happens to log in to a server from a terminal that has been fully compromised, then the other past and future user's sessions initiated from honest terminals stay secure. We define the security model for Human Authenticated Key Exchange (HAKE) protocols and first propose two generic protocols based on human-compatible (HC) function family, password-authenticated key exchange (PAKE), commitment, and authenticated encryption. We prove our HAKE protocols secure under reasonable assumptions and discuss efficient instantiations. We thereafter propose a variant where the human gets help from a small device such as RSA SecurID. This permits to implement an HC function family with stronger security and thus allows to weaken required assumptions on the PAKE. This leads to the very efficient HAKE which is still secure in case of strong corruptions. We believe that our work will promote further developments in the area of human-oriented cryptography.

Category / Keywords: cryptographic protocols / Human computation, Key exchange, One-time passwords, PAKE, Strong corruptions.

Original Publication (with major differences): CSF2017 - 30th IEEE Computer Security Foundations Symposium

Date: received 8 Jun 2017, last revised 8 Jun 2017

Contact author: sasha at gatech edu, shanchen at gatech edu, pierre-alain dupont at ens fr, David Pointcheval at ens fr

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Version: 20170608:200835 (All versions of this report)

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