International Association for Cryptologic Research

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Post-quantum TLS without handshake signatures

Authors:
Sofía Celi
Armando Faz Hernández
Peter Schwabe
Douglas Stebila
Thom Wiggers
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Presentation: Slides
Abstract: We present KEMTLS, an alternative to the TLS 1.3 handshake that uses key-encapsulation mechanisms (KEMs) instead of signatures for server authentication. Among existing post-quantum candidates, signature schemes generally have larger public key/signature sizes compared to the public key/ciphertext sizes of KEMs: by using an IND-CCA-secure KEM for server authentication in post-quantum TLS, we obtain multiple benefits. A size-optimized post-quantum instantiation of KEMTLS requires less than half the bandwidth of a size-optimized post-quantum instantiation of TLS 1.3. In a speed-optimized instantiation, KEMTLS reduces the amount of server CPU cycles by almost 90% compared to TLS 1.3, while at the same time reducing communication size, reducing the time until the client can start sending encrypted application data, and eliminating code for signatures from the server's trusted code base.
Video: https://youtu.be/TZMgRnSV3pk?t=3175
BibTeX
@misc{rwc-2021-35516,
  title={Post-quantum TLS without handshake signatures},
  note={Video at \url{https://youtu.be/TZMgRnSV3pk?t=3175}},
  howpublished={Talk given at RWC 2021},
  author={Sofía Celi and Armando Faz Hernández and Peter Schwabe and Douglas Stebila and Thom Wiggers},
  year=2021
}