Plaintext checkable signcryption

Abstract

Digital signature guarantees the authenticity and encryption ensures the confidentiality of a transmitted message. Signcryption, as the name indicates, is a primitive which serves both these purpose with added efficiency and features. In this paper, we introduce a variant of signcryption called Plaintext Checkable Signcryption (PCSC), which extends signcryption by the following functionality: given a signcryptext c, a plaintext m and the corresponding public values, it is universally possible to check whether c is a signcryption of m. The security requirements of such a primitive is studied and a suitable model of security is proposed. Moreover, we provide efficient generic model construction for PCSC based on “Encrypt-then-Sign” paradigm using an arbitrary partially trapdoor one-way function and a signature scheme. Finally, the construction is shown to be secure in the proposed model.