Anonymous signcryption is synonyms of ring signcryption which provides anonymity of the sender along with the advantages of signcryption. Multi receiver signcryption is suited for situation where a sender wants to send a message to multiple receivers in the confidential and authenticated way. This paper proposes an identity based anonymous signcryption scheme in multireceiver setting. It also p...

A signcryption scheme is secure only if it satisfies both the confidentiality and the unforgeability properties. All the ID based signcryption schemes presented in the standard model till now do not have either the confidentiality or the unforgeability or both of these properties. Cryptanalysis of some of the schemes have been proposed already. In this work, we present the security attack on ‘S...

Generalized signcryption (GSC) can adaptively work as an encryption scheme, a signature scheme or a signcryption scheme with only one algorithm. It is more suitable for the storage constrained setting. In this paper, motivated by Paterson–Schuldt’s scheme, based on bilinear pairing, we first proposed an identity based generalized signcryption (IDGSC) scheme in the standard model. To the best of...

This article presents a new signcryption scheme which is based on the Schnorr digital signature algorithm. The new scheme represents my personal contribution to signcryption area. I have been implemented the algorithm in a program and here are provided the steps of the algorithm, the results and some examples. The paper also contains the presentation of the original Signcryption scheme, based o...

Signcryption is an important cryptographic primitive that simultaneously achieves confidentiality and authentication in an efficient manner. In 2008, Luo et al. introduced the notion of certificate-based signcryption and proposed the first construction of certificate-based signcryption. However, their scheme is insecure under the key replacement attack and also does not provide insider security...

Signcryption schemes provide an efficient messaging system for data that needs to be sent with data confidentiality, data integrity and data origin authentication. However, the bandwidth overhead for the use of signcryption in a network in which a large number of messages need to be sent may be high. Motivated by aggregate signature schemes, we propose the concept of an aggregate signcryption s...

In this paper, we propose a generic method to construct Hierarchical Identity-Based Signcryption scheme. Using this method, a Hierarchical Identity-Based Signcryption scheme can be converted from any Hierarchical Identity-Based Encryption scheme. Then, we give a concrete instantiation, which is the first constant-size fully secure hierarchical identity-based signcryption scheme in the standard ...

Certificateless public-key encryption has recently been proposed as an attractive alternative to certificate-based and identity-based encryption schemes. The attraction of certificateless PKE is that it combines the implicit public key authentication of an identity-based scheme with the escrow-free property of a certificate-based scheme. However, all the certificateless schemes that have been t...

Signcryption can offer authentication and confidentiality simultaneously with better efficiency than traditional signature-then-encryption approach. Ring signature enables a user to conscribe arbitrarily a group of ring members and sign a message on behalf of the ring (which includes himself) without revealing his real identity. By integrating the notion of signcryption and ring signature, ring...

Signcryption is a cryptographic primitive which performs encryption and signature in a single logical step with the cost lower than signature-then-encryption approach.. In this paper we gave attacks on confidentiality and unforgeability of two identity based signcryption schemes without random oracles. Further we proposed an improved identity based signcryption scheme without random oracles. We...