*18:17*[Pub][ePrint] Enhanced Lattice-Based Signatures on Reconfigurable Hardware, by Thomas P\\\"oppelmann and L{\\\'e}o Ducas and Tim G\\\"uneysu

The recent BLISS signature scheme showed that lattice-based constructions have evolved to practical alternatives to RSA or ECC. Besides reasonably small signatures with 5600 bits for a 128-bit level of security, BLISS enables extremely fast signing and signature verification in software. However, due to the complex sampling of Gaussian noise with high precision, it is not clear whether this scheme can be mapped efficiently to embedded devices. In particular, the software approach of using large precomputed tables for Gaussian sampling cannot be transferred to constrained computing environments, such as FPGAs with limited memory. In this work we present techniques for an efficient CDT-based Gaussian sampler on reconfigurable hardware involving Peikert\'s convolution lemma and the Kullback-Leibler divergence. Based on our enhanced sampler design, we provide a first BLISS architecture for Xilinx Spartan-6 FPGAs that integrates fast FFT/NTT-based polynomial multiplication, sparse multiplication, and a Keccak hash function. With on our core a signing operations requires 123 \\textmu s on average, using 2,584 slices, 8 BRAMs, and 6 DSPs. Verification takes slightly less with 70 \\textmu s.