A New Efficient Multiple Messages Signcryption Scheme with Public Verifiability

Abstract

Signcryption is a cryptographic primitive first proposed by Zheng in 1997 to combine the functionality of a digital signature scheme with that of an encryption scheme. Public verifiability is very important requirement for a signcryption scheme to settle a repudiation in case of a dispute. Recently in [1], a new efficient public key multi-messages signcryption scheme was introduced. This scheme is based on the intractability of Discrete Logarithm Problem (DLP) and used a multi-key generator to simultaneously signcrypts multiple messages in a logical single step, but it doesn’t achieve public verifiability. In this paper we introduce a new multiple messages signcryption scheme which achieves the same efficiency as that of the scheme in [1] but with the following advantages: (i) It is publicly verifiable. (ii) It uses a simple and dynamic multiple keys generation routine (MKGR). (iii) Its security is based on the intractability of three hard problems: DLP, Diffie-Hellman Problem (DHP) and reversing a One-Way Hash Function (OWHF).