Cryptology ePrint Archive: Report 2020/1165
Practical Isogeny-Based Key-exchange with Optimal Tightness
Bor de Kock and Kristian Gjøsteen and Mattia Veroni
Abstract: We exploit the Diffie-Hellman-like structure of CSIDH to build a quantum-resistant authenticated key-exchange algorithm. Our security proof has optimal tightness, which means that the protocol is efficient even when instantiated with theoretically-sound security parameters. Compared to previous isogeny-based authenticated key-exchange protocols, our scheme is extremely simple, its security relies only on the underlying CSIDH-problem and it has optimal communication complexity for CSIDH-based protocols.
Our security proof relies heavily on the rerandomizability of CSIDH-like problems and carries on in the ROM.
Category / Keywords: cryptographic protocols / Post-quantum, isogenies, key-exchange, provable-security, tightness, rerandomization.
Date: received 24 Sep 2020
Contact author: mattia veroni at ntnu no
Available format(s): PDF | BibTeX Citation
Note: This paper, with minor modifications, will appear at SAC2020.
Version: 20200925:184752 (All versions of this report)
Short URL: ia.cr/2020/1165
[ Cryptology ePrint archive ]