Cryptographic decoding of the Leech lattice

Abstract

Advancements in quantum computing have spurred the development of new asymmetric cryptographic primitives that are conjectured to be secure against quantum attackers. One promising class of these primitives is based on lattices, leading to encryption protocols based on the Learning With Errors (LWE) problem. Key exchange algorithms based on this problem are computationally efficient and enjoy on a strong worst-case hardness guarantee. However, despite recent improvements, the resulting handshake sizes are still significantly larger than those in use today. This thesis looks at the possibility of applying the Leech lattice code to one such scheme, with the goal of decreasing the size of the resulting handshake. We also look at the feasibility of a cryptographically safe implementation of a Leech lattice decoder, and the resulting impact on efficiency.