Efficient Compression of SIDH Public Keys

Speaker: 
David Jao
Date: 
Thu, Mar 23, 2017
Location: 
University of Waterloo
Conference: 
PIMS CRG in Explicit Methods for Abelian Varieties
Abstract: 
Supersingular isogeny Diffie-Hellman (SIDH) is an attractive candidate for post-quantum key exchange, in large part due to its relatively small public key sizes. In this work we develop methods to reduce the size of public keys in isogeny-based cryptosystems by more than a factor of two, with performance cost comparable to that of a round of standalone SIDH key exchange, using a combination of techniques from the theory of elliptic curve descent, faster bilinear pairings, and windowed Pohlig-Hellman for discrete logarithms. Our results provide SIDH public keys of 330 bytes for the 128-bit quantum security level, far smaller than any other available alternative, and further strengthen the case for SIDH as a promising post-quantum primitive. Joint work with Craig Costello, Patrick Longa, Micahel Naehrig, Joost Renes, and David Urbanik