Abstract: All known round optimal (i.e., two-move) blind signature schemes either need a common reference string, rely on random oracles, or assume the hardness of some interactive assumption. At Eurocrypt 2010, Fischlin and Schröder showed that a broad class of three-move blind signature scheme cannot be instantiated in the standard model based on any non-interactive assumption. This puts forward the question if round optimal blind signature schemes exist in the standard model. Here, we give a positive answer presenting the first round optimal blind signature scheme that is secure in the standard model without any setup assumptions. Our solution does not need interactive assumptions.
Merged into (Schröder, Unruh, Garg, Rao, Sahai, Round Optimal Blind Signatures, 2011)