Invisible designated confirmer signatures without random oracles
Victor K. Wei · 2007
We present the first O(1)-size designated confirmer signatures (DCS) with security in the state-of-the-art model of Camenisch and Michels, Eurocrypt 2000, without random oracles. In particular, we achieve the security notion called the "invisibility of signature" therein. We do so by a simple upgrade of Gentry, et al. [7]. Then we also present O(1)-size identity-based DCS without random oracle by without invisibility, and O(1)-size undeniable signature without random oracle and with invisibility.