Hybrid key exchange in TLS 1.3


Hybrid key exchange refers to using multiple key exchange algorithms simultaneously and combining the result with the goal of providing security even if all but one of the component algorithms is broken. It is motivated by transition to post-quantum cryptography. This document provides a construction for hybrid key exchange in the Transport Layer Security (TLS) protocol version 1.3.

Keywords: key exchange, Transport Layer Security (TLS), post-quantum cryptography


Douglas Stebila, Scott Fluhrer, Shay Gueron. Hybrid key exchange in TLS 1.3. Internet-Draft. Internet Engineering Task Force, August 2023. Draft-08. © IETF Trust and the authors.



  • 2022-06-27: European Space Agency workshop on Secure Communications for Space Missions in the Post-Quantum Era. (PDF slides)
  • 2021-07-28: IETF 111. (PDF slides)