Douglas Stebila

Quantum key distribution in the classical authenticated key exchange framework

Comparison of security properties of various classical and quantum AKE protocols.

Abstract

Key establishment is a crucial primitive for building secure channels in a multi-party setting. Without quantum mechanics, key establishment can only be done under the assumption that some computational problem is hard. Since digital communication can be easily eavesdropped and recorded, it is important to consider the secrecy of information anticipating future algorithmic and computational discoveries which could break the secrecy of past keys, violating the secrecy of the confidential channel.

Quantum key distribution (QKD) can be used generate secret keys that are secure against any future algorithmic or computational improvements. QKD protocols still require authentication of classical communication, although existing security proofs of QKD typically assume idealized authentication. It is generally considered folklore that QKD when used with computationally secure authentication is still secure against an unbounded adversary, provided the adversary did not break the authentication during the run of the protocol.

We describe a security model for quantum key distribution extending classical authenticated key exchange (AKE) security models. Using our model, we characterize the long-term security of the BB84 QKD protocol with computationally secure authentication against an eventually unbounded adversary. By basing our model on traditional AKE models, we can more readily compare the relative merits of various forms of QKD and existing classical AKE protocols. This comparison illustrates in which types of adversarial environments different quantum and classical key agreement protocols can be secure.

Keywords: quantum key distribution, authenticated key exchange, cryptographic protocols, security models

Reference

Michele Mosca, Douglas Stebila, Berkant Ustaoglu. Quantum key distribution in the classical authenticated key exchange framework. In Philippe Gaborit, editor, Proc. 5th International Conference on Post-Quantum Cryptography (PQCrypto) 2013, LNCS, vol. 7932, pp. 136-154. Springer, June 2013. © Springer.

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Presentations

• 2012-09-13: QCRYPT 2012. (PDF slides)

BibTeX

@inproceedings{PQCrypto:MosSteUst13,
 	Author = {Michele Mosca and Douglas Stebila and Berkant Ustaoglu},
 	Booktitle = {Proc. 5th International Conference on Post-Quantum Cryptography (PQCrypto) 2013},
 	Doi = {10.1007/978-3-642-38616-9 9},
 	Editor = {Philippe Gaborit},
 	Month = {June},
 	Pages = {136--154},
 	Publisher = {Springer},
 	Series = {LNCS},
 	Title = {Quantum key distribution in the classical authenticated key exchange framework},
 	Volume = {7932},
 	Year = {2013}
 }

Funding

• Natural Sciences and Enginering Research Council (NSERC) of Canada Discovery grant
• Natural Sciences and Enginering Research Council (NSERC) of Canada SPG FREQUENCY grant
• Natural Sciences and Enginering Research Council (NSERC) of Canada CREATE grant
• QuantumWorks
• MITACS
• Canadian Institute for Advanced Research (CIFAR)
• Ontario Research Fund
• Government of Canada
• Province of Ontario