Pairing-Free Blind Signatures from Standard Assumptions in the ROM

Blind Signatures are a useful primitive for privacy-preserving applications such as electronic payments, e-voting, and anonymous credentials. However, existing practical blind signature schemes based on standard assumptions require either pairings or lattices. We present the first practical construction of a round-optimal blind signature in the random oracle model based on standard assumptions without resorting to pairings or lattices. This construction is secure under the strong RSA assumption and DDH (in pairing-free groups). We provide a NIZK-friendly signature based on strong RSA, with signature size of 4.28 KB and communication cost of 10.98 KB. Joint work with Julia Kastner (CWI) and Michael Reichle (ETH Zurich)