Signature Schemes

Digital signature constructions and the tightness of their security reductions.

Status	Problem	Tags
	No round-optimal pairing-free blind signature Open for a polynomial query budget. The impossibility is proved when \(\mathsf{User}_2\) and \(\mathsf{Verify}\) together make \(O(\log\lambda)\) random-oracle queries, including when oracle outputs contain group elements; the superpolynomial message space hypothesis is retained. 5 open	Black Box Separations Blind Signatures Generic Group Model Signature Schemesggmimpossibilityadaptation (ai)
	Three moves from DL, ROM only Open: three moves, black-box in the group, ROM only, from DL alone. Three moves is achieved from DDH in the ROM and from DL in AGM+ROM; four moves is achieved from DL in the ROM. 5 open	Blind Signatures Random Oracle Model Signature Schemes Tight Reductionsromassumption
	Single-session lattice Chevallier-Mames tightness Open: whether the one-session lattice translation of the Chevallier-Mames signature has a tight SUF-CMA reduction to search Module-LWE, or whether the paper’s two-fold parallel repetition (which doubles signature size and signing time) is inherent to a tight proof of this shape. 4 open	Learning With Errors Signature Schemes Tight Reductionsromtight-bound