This article proposes a provably secure aggregate signcryption scheme in random oracles. Security of the scheme is based on computational infeasibility of solving Decisional Bilinear Diffie-Hellman Problem and Discrete Logarithm Problems. Confidentiality and authenticity are two fundamental security requirements of Public key Cryptography. These are achieved by encryption scheme and digital sig...

Certificateless cryptography eliminates the need of certificates in the PKI and solves the inherent key escrow problem in the ID-based cryptography. Recently, Du and Wen proposed a short certificateless signature scheme (SCLS) without MapToPoint hash function, and the signature size is short enough with only half of the DSA signature. In this paper, after the detailing the formal of certificate...

Signcryption is a cryptographic primitive that aims at providing confidentiality and the sender’s identity authentication in a logic step, at lower computational costs and communication overheads than sign-then-encrypt way. Recently, Yu et al.[1] proposed a new identity based signcryption scheme in standard model. However, in this paper, we show that the scheme still has some security weaknesse...

A (t,n) threshold signature scheme allows t or more group members to generate signatures on behalf of a group with nmembers. In contrast to the traditional public key cryptography based on public key infrastructure (PKI) and identity-based public key cryptography (IDPKC), certificateless public key cryptography (CL-PKC) offers useful properties as it does not require any certificates to ensure ...

Signcryption enables a user to perform digital signature for providing authenticity and public key encryption for providing message confidentiality simultaneously in a single logical step with a cost lesser than sign-thenencrypt approach. As the concept of ring signcryption emerged, various practical applications like electronic transaction protocol and key management protocols, felt the requir...

Certificateless public key cryptography (CLPKC), with properties of no key escrow and no certificate, has received a lot of attention since its invention. However, membership revocation in certificateless cryptosystem still remains a non-trivial problem: the existing solutions are not practical for use due to either a costly mediator or enormous computation (secret channel). In this paper, we p...

The signcryption is a relatively new cryptographic technique that is supposed to fulfill the functionalities of encryption and digital signature in a single logical step. Although several signcryption schemes are proposed over the years, some of them are proved to have security problems. In this paper, the security of Han et al.’s signcryption scheme is analyzed, and it is proved that it has ma...

Signcryption is a cryptographic primitive which could provide authentication and confidentiality simultaneously with a computational cost lower than signing and encryption respectively, while the ring signcryption has anonymity in addition to authentication and confidentiality. In order to design an identitybased threshold ring signcryption, this paper presented an efficient identity-based thre...

Abstract In recent years, network coding has received extensive attention and been applied to various computer systems, since it mathematically proven enhance the robustness maximize throughput. However, is well-known that extremely vulnerable pollution attacks. Certificateless scheme (CLNS) a recently proposed mechanism defend against attacks for coding, which avoids tedious management of cert...