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Lengths May Break Privacy – Or How to Check for Equivalences with Length

Cheval, Vincent, Cortier, Véronique, Plet, Antoine (2013) Lengths May Break Privacy – Or How to Check for Equivalences with Length. In: 25th International Conference on Computer Aided Verification (CAV'13), July 2013, St Petersburg, Russia. (doi:10.1007/978-3-642-39799-8_50) (KAR id:46726)

Abstract

Security protocols have been successfully analyzed using symbolic models, where messages are represented by terms and protocols by processes. Privacy properties like anonymity or untraceability are typically expressed as equivalence between processes. While some decision procedures have been proposed for automatically deciding process equivalence, all existing approaches abstract away the information an attacker may get when observing the length of messages.

In this paper, we study process equivalence with length tests. We first show that, in the static case, almost all existing decidability results (for static equivalence) can be extended to cope with length tests.

In the active case, we prove decidability of trace equivalence with length tests, for a bounded number of sessions and for standard primitives. Our result relies on a previous decidability result from Cheval et al (without length tests). Our procedure has been implemented and we have discovered a new flaw against privacy in the biometric passport protocol.

Item Type: Conference or workshop item (Paper)
DOI/Identification number: 10.1007/978-3-642-39799-8_50
Uncontrolled keywords: Cryptographic protocols, Formal verification, Symbolic model, Automatic, Equivalence properties, Lengh attacks
Subjects: Q Science > QA Mathematics (inc Computing science) > QA 75 Electronic computers. Computer science
Q Science > QA Mathematics (inc Computing science) > QA 9 Formal systems, logics
Divisions: Divisions > Division of Computing, Engineering and Mathematical Sciences > School of Computing
Depositing User: Vincent Cheval
Date Deposited: 23 Jan 2015 11:13 UTC
Last Modified: 16 Nov 2021 10:18 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46726 (The current URI for this page, for reference purposes)

University of Kent Author Information

Cheval, Vincent.

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