Signcryption is a cryptographic primitive that fulfills both the functions of digital signature and public key encryption simultaneously, at a cost significantly lower than that required by the traditional signature-then-encryption approach. In this paper, we address a question whether it is possible to construct a hybrid signcryption scheme in the certificateless setting. This question seems t...

The hybrid signcryption scheme based on certificateless public key cryptography avoids the complexity of certificate management existing in the traditional public key cryptography and the inherent key escrow problem existing in identity-based public key cryptography. The certificateless hybrid signcryption scheme combined with certificateless signcryption key encapsulation mechanism and data en...

Often authentication and confidentiality are required as simultaneous key requirements in many cryptographic applications. The cryptographic primitive called signcryption effectively implements the same and while most of the public key based systems are appropriate for small messages, hybrid encryption (KEM-DEM) provides an efficient and practical way to securely communicate very large messages...

Certificateless public key cryptography (CL-PKC) is a useful method in order to solve the problems of traditional public key infrastructure (i.e., large amount of computation, storage and communication costs for managing certificates) and ID-based public key cryptography (i.e., key escrow problem), simultaneously. A signcryption scheme is an important primitive in cryptographic protocols which ...

Generalized signcryption is a new cryptographic primitive which works as a signcryption scheme, a signature scheme and an encryption scheme as per need. Recently Ji et al. proposed a security model for certificateless generalized signcryption scheme and also proposed a scheme which they claim is secure under the proposed security model. In this paper we show that Ji et al. scheme is not existen...

certificateless public key cryptography (cl-pkc) is a useful method in order to solve the problems of traditional public key infrastructure (i. e. large amount of computation, storage and communication cost for managing certificates) and id-based public key cryptography (i. e. key escrow problem), simultaneously. a signcryption scheme is an important primitive in cryptographic protocols which p...

Certificateless cryptography; Aggregate signcryption; Random oracle model; Bilinear pairing Abstract The concept of aggregate signcryption was first introduced in 2009 by Selvi et al. [Identity based aggregate signcryption schemes, Lecture Notes in Computer Science 5922 LNCS, 2009, pp. 378–397]. The aggregation process of these schemes reduces the amount of exchanged information and is particul...

Generalized Signcryption is a fresh cryptographic primitive that not only can obtain encryption and signature in a single operation, but also provives encryption or signature alone when needed. This paper gives a formal definition of certificateless generalized signcryption and its security model is present. A concrete certificateless generalized signcryption scheme is also proposed in this paper.

Signcryption is a cryptographic primitive which can offer simultaneously security requirements of confidentiality and authentication, and is more efficient than the traditional sign-then-encrypt way. Recently, Liu et al. proposed the first certificateless signcryption scheme in the standard model. However, their scheme is proved to have some security weaknesses. In this paper, we propose a corr...

Certificateless-based signcryption overcomes inherent shortcomings in traditional Public Key Infrastructure (PKI) and Key Escrow problem. It imparts efficient methods to design PKIs with public verifiability and cipher text authenticity with minimum dependency. As a classic primitive in public key cryptography, signcryption performs validity of cipher text without decryption by combining authen...