Douglas Stebila

Prototyping post-quantum and hybrid key exchange and authentication in TLS and SSH

Test results for key exchange using post-quantum and hybrid key encapsulation mechanisms in TLS and SSH implementations

Abstract

Once algorithms for quantum-resistant key exchange and digital signature schemes are selected by standards bodies, adoption of post-quantum cryptography will depend on progress in integrating those algorithms into standards for communication protocols and other parts of the IT infrastructure. In this paper, we explore how two major Internet security protocols, the Transport Layer Security (TLS) and Secure Shell (SSH) protocols, can be adapted to use post-quantum cryptography.

First, we examine various design considerations for integrating post-quantum and hybrid key exchange and authentication into communications protocols generally, and in TLS and SSH specifically. These include issues such as how to negotiate the use of multiple algorithms for hybrid cryptography, how to combine multiple keys, and more. Subsequently, we report on several implementations of post-quantum and hybrid key exchange in TLS 1.2, TLS 1.3, and SSHv2. We also report on work to add hybrid authentication in TLS 1.3 and SSHv2. These integrations are in Amazon s2n and forks of OpenSSL and OpenSSH; the latter two rely on the liboqs library from the Open Quantum Safe project.

Keywords: post-quantum cryptography, TLS, SSH

Reference

Eric Crockett, Christian Paquin, Douglas Stebila. Prototyping post-quantum and hybrid key exchange and authentication in TLS and SSH. In NIST 2nd Post-Quantum Cryptography Standardization Conference 2019. August 2019. © The authors.

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Presentations

• 2020-11-17: Indian Workshop on Post-Quantum Cryptography. (PDF slides)
• 2019-08-22: NIST 2nd Post-Quantum Cryptography Standardization Conference 2019, Santa Barbara, California. (PDF slides)

BibTeX

@inproceedings{NISTPQC:CroPaqSte19,
 	Author = {Eric Crockett and Christian Paquin and Douglas Stebila},
 	Booktitle = {NIST 2nd Post-Quantum Cryptography Standardization Conference 2019},
 	Month = {August},
 	Title = {Prototyping post-quantum and hybrid key exchange and authentication in {TLS} and {SSH}},
 	Year = {2019}
 }

Funding

• Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery grant RGPIN-2016-05146
• NSERC Discovery Accelerator Supplement grant RGPIN-2016-05146