Please note: This PhD seminar will be given online.
Sebastian Verschoor, PhD candidate
David R. Cheriton School of Computer Science
Distance bounding protocols convince a verifier of both the identity and physical proximity of a prover by timing the delay between sending a challenge and receiving a response. Terrorist fraud is an attack on distance bounding in which a far-away dishonest prover and nearby accomplice convince the verifier that the prover is nearby. Recent work has combined distance bounding with quantum cryptography by introducing three protocols that encode the response and/or challenge as qubits, optionally combined with standard techniques from classical distance bounding to prevent terrorist fraud.
In this talk I show that in the quantum setting these countermeasures either lead to extraction of the long-term key or are insufficient to prevent terrorist fraud, by describing an efficient attack against each countermeasure and each protocol. I improve the existing security analysis by considering quantum strategies for the adversary and by highlighting some inaccuracies in the original analysis. Finally I discuss a new protocol, combining classical distance bounding with quantum key distribution to achieve information theoretical security.
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