Designated verifier signatures were introduced in the middle of the 90’s by Jakobsson, Sako and Impagliazzo, and independenty patended by Chaum as private signatures. In this setting, a signature can only be verified by a unique and specific user. At Crypto’03, Desmedt suggested the problem of generalizing the designated verifier signatures. In this case, a signature should be intended to a spe...

Multi-Designated Verifier Signatures (MDVS) are privacy-oriented signatures that can only be verified by a set of users specified by the signer. We propose two new generic constructions of MDVS from variants of existing cryptographic schemes, which are ring signature from anonymous subset and multi-chameleon hash. We first devise a single add-on protocol which enables many existing identity-bas...

An aggregate signature scheme is a digital signature that supports aggregation: Given n signatures on n distinct messages from n distinct users, it is possible to aggregate all these signatures into a single short signature. This single signature (and the n original messages) will convince the verifier that the n users did indeed sign the n original messages (i.e., user i signed message Mi for ...

This paper first introduces the concept of universal designated verifier ring signature (UDVRS), which not only allows members of a group to sign messages on behalf of the group without revealing their identities, but also allows any holder of the signature (not necessary the signer) to designate the signature to any designated verifier. According to whether the designator has a registered publ...

Identity-based proxy ring signature concept was introduced by Cheng et al. in 2004. This primitive is useful where the privacy of proxy signers is required. In this paper, the first short provably secure identity-based proxy ring signature scheme from RSA assumption has been proposed. In addition, the security of the proposed scheme tightly reduces to the RSA assumption, and therefore, the prop...

We propose unique ring signatures that simplify and capture the spirit of linkable ring signatures. We provide an instantiation which can be more tightly related to the CDH problem and DDH problem in the random oracle model, leading to the most efficient linkable/unique ring signature.