Organizer: Moritz Horsch, TU Darmstadt
Blind signatures are basic ingredients for privacy-preserving cryptographic applications such as e-voting, anonymous credentials, and Bitcoin. Due to the expected progress in cryptanalysis using new computing environments, lattice-based cryptography is a very promising alternative for current cryptographic applications. In this work, we present a new blind signature scheme that improves in many aspects upon the first (and currently only secure) lattice-based proposal introduced by Rückert (ASIACRYPT 2010). We obtain a practical construction that can be instantiated with any standard signature scheme based on the ``Fiat-Shamir with Aborts'' framework. In comparison to Rückert's proposal, our signing and verification keys are a factor of 64 and 4 smaller (respectively), the communication complexity required to produce a signature is a factor of 8 lower, and signatures are a factor of 128 shorter. Noticeably, they are even at most twice as long as standard signatures produced by lattice-based schemes recently submitted to NIST.