Generic constructions for universal designated-verifier signatures and identitybased signatures from standard signatures

The authors give a generic construction for universal (mutli) designated-verifier signature schemes from a large class of signature schemes, referred to as Class Copf. The resulting schemes are efficient and have two important properties. Firstly, they are provably DV-unforgeable, non-transferable and also non-delegatable. Secondly, the signer and the designated verifier can independently choose their cryptographic settings. The authors also propose a generic construction for (hierarchical) identity-based signature schemes from any signature scheme in Copf and prove that the construction is secure against adaptive chosen message and identity attacks. The authors discuss possible extensions of our constructions to identity-based ring signatures and identity-based designated-verifier signatures from any signature in Copf. Finally, the authors show that it is possible to combine the above constructions to obtain signatures with combined functionalities.