in Crypto 2011, LNCS vol. 6841, Springer, pp. 630-648, 2011. Merger of Round Optimal Blind Signatures by Schröder and Unruh and
"Round Optimal Blind Signatures in the Standard Model" by Sanjam Garg, Vanishree Rao, and Amit Sahai.
Constructing round-optimal blind signatures in the standard model has been a long standing open problem. In particular, Fischlin and Schröder recently ruled out a large class of three-move blind signatures in the standard model~(Eurocrypt'10). In particular, their result shows that finding security proofs for the well-known blind signature schemes by Chaum, and by Pointcheval and Stern in the standard model via black-box reductions is hard. In this work we propose the first round-optimal, i.e., two-move, blind signature scheme in the standard model (i.e., without assuming random oracles or the existence of a common reference string). Our scheme relies on the Decisional Diffie Hellman assumption and the existence of sub-exponentially hard 1-to-1 one way functions. This scheme is also secure in the concurrent setting.
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