In a directed signature scheme, a verifier can exclusively verify the signatures designated to himself, and shares with the signer the ability to prove correctness of the signature to a third party when necessary. Directed signature schemes are suitable for applications such as bill of tax and bill of health. This paper studies directed signatures in the identity-based setting. We first present...

In a proxy signature scheme, one original signer delegates a proxy signer to sign messages on behalf of the original signer. When the proxy signature is created, the proxy signer generates valid proxy signatures on behalf of the original signer. Based on Cha and Cheon’s ID-based signature scheme, a model of designated-verifier proxy signature scheme from the bilinear pairing is proposed. The pr...

-Electronic contract-signing is an important issue in Electronic Commerce. This paper proposed a novel abuse-free contract signing protocol based on convertible signature and non-interactive designated verifier proof. One interesting property is that the outcome evidences are standard RSA signatures, which makes the protocol be easily integrated into existing systems.

Ring signatures are an important primitive for protecting signers’ privacy while ensuring that a signature in question is indeed issued by some qualified user. This notion can be seen as a generalization of the well-known notion of group signatures. A group signature is a signature such that a verifier can establish its validity but not the identity of the actual signer, who can nevertheless be...

Cloud data owners encrypt their documents before outsourcing to provide their privacy. They could determine a search control policy and delegate the ability of search token generation to the users whose attributes satisfy the search control policy. Verifiable attribute-based keyword search (VABKS) where the users can also verify the accuracy of cloud functionality is one of such schemes. In thi...

A digital signature provides the authenticity of a signed message with respect to a public key and a certificate provides the authorization of a signer for a public key. Digital signature and certificate are generated independently by different parties, but they are verified by the same verifier who wants to verify the signature. In the point of a verifier, verifying two independent digital sig...

The authenticated encryption scheme allows one signer to generate an authenticated cipher-text so that no one except the designated verifier can recover the message and verify the message. In a (t, n) threshold authenticated encryption scheme, any t or more signers can generate an authenticated encryption for a message and send it to the designated verifier. Compared with the conventional encry...

Strong designated verifier signature (SDVS) is characterized by two properties; namely the nontransferability and the privacy of the signer’s identity (PSI). Non-transferability prevents anyone else other than the designated verifier to verify the signature, while PSI prevents a third party to distinguish between two different signers. In this paper, we propose a non-delegatable SDVS which uses...

Motivated by the conflict between authenticity and privacy in the digital signature, the notion of limited verifier signature was introduced [1]. The signature can be verified by a limited verifier, who will try to preserve the privacy of the signer if the signer follows some specified rules. Also, the limited verifier can provide a proof to convince a judge that the signer has indeed generated...

In ordinary digital signature schemes, anyone can verify signatures with signer’s public key. However it is not necessary for anyone to be convinced a justification of signer’s dishonorable message such as a bill. It is enough for a receiver only to convince outsiders of signature’s justification if the signer does not execute a contract. On the other hand there exist messages such as official ...