Paper 2017/757

CAKE: Code-based Algorithm for Key Encapsulation

Paulo S. L. M. Barreto, Shay Gueron, Tim Gueneysu, Rafael Misoczki, Edoardo Persichetti, Nicolas Sendrier, and Jean-Pierre Tillich


Current widely-used key exchange (KE) mechanisms will be vulnerable to quantum attacks when sufficiently strong quantum computers become available. Therefore, devising quantum-resistant replacements that combine efficiency with solid security guarantees is an important and challenging task. This paper proposes several contributions towards this goal. First, we introduce CAKE, a key encapsulation algorithm based on the QC-MDPC McEliece encryption scheme, with two major improvements: a) the use of ephemeral keys that defeats a recent reaction attack against MDPC decoding of the corresponding encryption scheme and b) a highly efficient key generation procedure for QC-MDPC-based cryptosystems. Then, we present an authenticated key exchange protocol based on CAKE, which is suitable for the Internet Key Exchange (IKE) standard. We prove that CAKE is IND-CPA secure, that the protocol is SK-Secure, and suggest practical parameters. Compared to other post-quantum schemes, we believe that CAKE is a promising candidate for post-quantum key exchange standardization.

Note: To appear at IMACC 2017

Available format(s)
Public-key cryptography
Publication info
Preprint. MINOR revision.
Contact author(s)
rafa misoczki @ gmail com
2017-10-23: last of 2 revisions
2017-08-07: received
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Creative Commons Attribution


      author = {Paulo S.  L.  M.  Barreto and Shay Gueron and Tim Gueneysu and Rafael Misoczki and Edoardo Persichetti and Nicolas Sendrier and Jean-Pierre Tillich},
      title = {CAKE: Code-based Algorithm for Key Encapsulation},
      howpublished = {Cryptology ePrint Archive, Paper 2017/757},
      year = {2017},
      note = {\url{}},
      url = {}
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