In a paper recently published in ICALP 2005, Lipmaa, Wang and Bao identified a new essential security property, non-delegatability, of designated verifier signature (DVS) schemes. Briefly, in a non-delegatable DVS scheme, neither a signer nor a designated verifier can delegate the signing rights to any third party T without revealing their secret keys. We show that the Susilo-ZhangMu identity-b...

The problem of generalization of (single) designated verifier schemes to several designated verifiers was proposed by Desmedt in 2003. The paper proposes eight new Identity Based Strong Bi-Designated Verifier Signature Schemes in which the two designated verifiers may not know each other. The security and the computational efficiency of the schemes are also analyzed.

The notion of Universal Designated Verifier Signature (UDVS), introduced by Steinfeld et al. in Asiacrypt 2003, allows any holder of a signature to convince any designated verifier that the signer indeed generated the signature without revealing the signature itself, while the verifier cannot transfer the proof to convince anyone else of this fact. Such signature schemes can protect the privacy...

We propose in this paper a new voting scheme where the voter, while receiving a receipt for his/her vote allowing further contestations, cannot use it to reveal the vote to other unspecified entities, and therefore cannot be forced to do so. The scheme is based on the concept of strong designated verifier signature scheme, and is very cheap in both computation and data communication, regarding ...

Braids groups provide an alternative to number theoretic public cryptography and can be implemented quite efficiently. The paper proposes five signature schemes: Proxy Signature, Designated Verifier, Bi-Designated Verifier, Designated Verifier Proxy Signature And Bi-Designated Verifier Proxy Signature scheme based on braid groups. We also discuss the security aspects of each of the proposed sch...

Universal Designated-Verifier Signature (UDVS) schemes are digital signature schemes with ad-ditional functionality which allows any holder of a signature to designate the signature to any desireddesignated-verifier such that the designated-verifier can verify that the message was signed by thesigner, but is unable to convince anyone else of this fact.Since UDVS schemes reduce t...

The security of strong designated verifier (SDV) signature schemes has thus far been analyzed only in a two-user setting. We observe that security in a twouser setting does not necessarily imply the same in a multi-user setting for SDV signatures. Moreover, we show that existing security notions do not adequately model the security of SDV signatures even in a twouser setting. We then propose re...

An attribute-based signature (ABS), is a cryptographic scheme where someone can sign message using any kind of predicates verified by the attributes he owns. For such scheme, it expected to be impossible for users collude if none them originally able on his own. The main advantage solution that signer remain anonymous in set fulfilling chosen predicate. It then used authentication instance. In ...