Fast verification and public key storage optimization for unstructured lattice-based signatures

International audienceA recent work of Sipasseuth, Plantard and Susilo proposed to accelerate lattice-based signature verifications and compress public key storage at the cost of a precomputation on a public key. This first approach, which focused on a restricted type of key, did not include most NIST candidates or most lattice representations in general. In this work, we first present a way to improve even further both their verification speed and their public key compression capability by using a generator of numbers that better suit the method needs. We then also generalize their framework to apply to q-ary lattice schemes as well as classical lattices using Hermite Normal Form, improving their security and applicable scope, thus exhibiting potential trade-offs to accelerate lattice-based signature verification in general and compression of the public key on the verifier side for unstructured lattices