Research On ID-based Signature And Signcryption Schemes

In an identity-based cryptosystem, users’public key is directly derived from their recognized identity, e.g. telephone number, email address, and so on. It only need to verify users’identity to judge their public key’s validity, and thus e-liminating the process of certificate authentication. In2001, Boneh and Franklin constructed an ID-based encryption scheme using the cryptographic technique, bi-linear pairings. Since then, the ID-based cryptosystem has been rapidly developed. Many ID-based signature and signcryption schemes with additional properties have been proposed, such as, ID-based blind signature, ID-based group signature, ID-based (strong) designated verifier signature, ID-based universal signature scheme, ID-based signcryption scheme, and so on.In this thesis, we focus on three types ID-based signature and signcryption schemes:ID-based Strong Designated Verifier Signature (ID-SDVS), ID-based U-niversal Designated Verifier Signcryption (ID-UDVSC) and ID-based Signcryption with Restrictive Unsigncryption (ID-SRU). Our main contributions are summarized as follows.1. We propose a new security concept, full non-delegatability, for the strong des-ignated verifier signature schemes (SDVS)."We also analyze security of existing SDVS schemes and find that all of them are vulnerable and insecure under this new security concept. Moreover, we construct an ID-based SDVS scheme with the property of full non-delegatability (ID-SDVS).2. We propose and construct an new ID-based universal designated verifier sign-cryption scheme (ID-UDVSC). Comparing with the previous schemes, the pro-posed UDVSC scheme can protect the signature’s privacy in a public trans-mission channel and improve the practical applicability of the UDVS scheme’s. Moreover, the transmission bandwidth between our ID-UDVSC scheme and pre-vious UDVS schemes is almost same.3. We propose a new signcryption scheme with additional property:Signcryption with Restrictive Unsigncryption (SRU). It aims to restrict the receiver’s ability to obtain the original message. We present the formal definition and security models for the SRU scheme in the ID-based setting. In the meantime, we also construct a concrete ID-based SRU scheme using bilinear pairings (ID-SRU).