G+G: A Fiat-Shamir Lattice Signature Based on Convolved Gaussians

ePrint Report: G+G: A Fiat-Shamir Lattice Signature Based on Convolved Gaussians

Julien Devevey, Alain Passelègue, Damien Stehlé

We describe an adaptation of Schnorr's signature to the lattice setting, which relies on Gaussian convolution rather than flooding or rejection sampling as previous approaches. It does not involve any abort, can be proved secure in the ROM and QROM using existing analyses of the Fiat-Shamir transform, and enjoys smaller signature sizes (both asymptotically and for concrete security levels).

eprint report flooding report signature