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...

Designated verifier signatures are intended to a specific and unique designated verifier, who is the only one person to check their validity. This paper proposes a new efficient non-delegatable strong designated verifier signature scheme based on identity based cryptography. We analyze the security of the scheme and compare its computational aspects with the other ID-SDVS schemes existing in li...

Multi signature is a signature scheme in which signers jointly generate a signature on a message. Threshold multisignature combines the traits of threshold signature and multisignature. In threshold multisignature, a group of users jointly generate a valid multisignature on a message and any one can verify the validity of the multisignature. However, in some applications the signed message is s...

A Designated Verifier Signature (DVS) scheme has the property of signer ambiguity, which can only convince a designated verifier of the signer’s identity. It is not allowed for the designated verifier to transfer the conviction to any third party. A Strong Designated Verifier Signature (SDVS) scheme further requires the designated verifier’s private key to perform the signature verification, so...

In 2004, Zhang and Xiao proposed a multisignature scheme based on ElGamal discrete logarithm algorithm which allows a signer group to sign a signature and a verifier group to verify the validity of the signed signature. In this paper, we will show that any verifier in the verifier group can break their scheme by replacing the valid signed message with another forged one which will also be authe...

Digital signatures are unsuitable for specific applications that sensitive on a personal or commercial level because they universally verifiable. Jakobsson et al. proposed the Designated Verifier Signature (DVS) system, which only allows intended verifier to validate message’s signature. It prohibits disclosure of conviction third party. This functionality is useful in require both authenticity...

People in authority may want to submit some messages anonymously on a famous website, while the maintainers may want to limit the times each person can submit messages on the website so as to save the storage space. More over, when people abuse the system, the maintainers want to find ways to identify their identities. To realize such a system, what we need are some methods that can protect use...

Based on ElGamal system, a group-oriented threshold signature and authenticated encryption scheme was put forward. After being signed by a signer group employing ) , ( n t threshold signature scheme, the message m was transmitted to a particular verifier group, and then the signature was verified through the cooperation of k ones from the verifier group with l members. Similarly, a general auth...