Two basic security requirements in communication are confidentiality and authentication. Signcryption is an ideal technique to transmit encrypted authenticated data. In view of the shortcomings existing signcryption schemes high elliptic curve cryptography (ECC), we design a ECC-based scheme evaluate it terms security, computational overhead, overhead. Finally, consider application our secure e...

Blind signatures have key role in real world applications like e-cash, e-voting etc. The first blind signature was proposed by Chaum under public key infrastructure(PKI) model. The inherent problem in PKI is the certificate management which is overcome by identity(ID) based system. The ID based system is susceptible to key escrow problem. By removing the inherent problems of both PKI and ID bas...

Certificateless signature is one of the most important security primitives which can be used to solve the key escrow problem existing in ID-based signature. The security of most certificateless signatures depends only based on one mathematical hard problem. This means that once the underlying hard problem is broken, the signature will be broken, too. In this paper, a certificateless signature w...

Many certificateless signature schemes using bilinear pairings have been proposed. But the relative computation cost of the pairing is approximately twenty times higher than that of the scalar multiplication over elliptic curve group. In order to improve the performance we propose a certificateless signature scheme without bilinear pairings. With the running time being saved greatly, our scheme...

Signcryption tag-KEM (key encapsulation mechanism with tag) allows the sender to encapsulate a symmetric key along with a tag so that the receiver can authenticate the sender, the key and the tag. In this paper, we introduce the notion of signcryption tag-KEM to the self-certified setting and ring signcryption, and construct a tag-KEM for self-certified ring signcryption, which only takes one p...

A signcryption scheme is a scheme that provides private and authenticated delivery of messages between two parties. It does this in a more eecient manner than a straightforward composition of an encryp-tion scheme with a signature scheme. An identity-based cryptosystem is one in which the public key may be any string (or may be derived from any string). In this paper we propose an identity-base...

Revocation functionality is crucial for the practicality of the public key cryptosystems including signcryption. When a user’s private key is corrupted by hacking or the period of a contract expires, the cryptosystems must provide a revocation method to revoke the misbehaving/compromised user. However, little work has been published on key revocation in identity-based signcryption. We propose a...

Proxy signature, a variant of digital signature, is in the limelight in recent years for secure communication. For instance, when a manager is occupied with business matters, or travelling on business, he has to delegate an agent to deal with his day-today office concerns. Therefore, a proxy signature scheme is necessary in this scenario. Although identity-based proxy signature schemes have bee...

Certificateless public key cryptography (CLPKC) is a paradigm to solve the inherent key escrow problem suffered by identity-based cryptography (IBC). While certificateless signature is one of the most important security primitives in CLPKC, there are relatively few proposed schemes in the literature. In this paper, we manage to construct an efficient certificateless signature scheme based on th...

In this paper, we present the first certificateless undeniable signature scheme. The scheme does not suffer from the key escrow problem, which is inherent in identity based cryptosystems. Also it can avoid the onerous management of certificates. Particularly, by using some cryptographic and mathematical techniques, we guarantee that the scheme’s two component protocols satisfy the properties of...