An Experiment in Ping-Pong Protocol Verification by Nondeterministic Pushdown Automata

Robert Glück
(DIKU, Dept. of Computer Science, University of Copenhagen)

An experiment is described that confirms the security of a well-studied class of cryptographic protocols (Dolev-Yao intruder model) can be verified by two-way nondeterministic pushdown automata (2NPDA). A nondeterministic pushdown program checks whether the intersection of a regular language (the protocol to verify) and a given Dyck language containing all canceling words is empty. If it is not, an intruder can reveal secret messages sent between trusted users. The verification is guaranteed to terminate in cubic time at most on a 2NPDA-simulator. The interpretive approach used in this experiment simplifies the verification, by separating the nondeterministic pushdown logic and program control, and makes it more predictable. We describe the interpretive approach and the known transformational solutions, and show they share interesting features. Also noteworthy is how abstract results from automata theory can solve practical problems by programming language means.

In John P. Gallagher, Rob van Glabbeek and Wendelin Serwe: Proceedings Third Workshop on Models for Formal Analysis of Real Systems and Sixth International Workshop on Verification and Program Transformation (MARS/VPT 2018), Thessaloniki, Greece, 20th April 2018, Electronic Proceedings in Theoretical Computer Science 268, pp. 169–184.
Published: 23rd March 2018.

ArXived at: http://dx.doi.org/10.4204/EPTCS.268.6 bibtex PDF
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