Distributed Signcryption Schemes with Formal Proof of Security

摘要

A distributed signcryption scheme was proposed by Mo and Varadharajan [18] in 2000 . Since then some more distributed signcryption schemes have been proposed [11,13]. But formal security models and security proofs have not been presented in any of these schemes. In this paper, we propose formal security model for distributed signcryption for confidentiality and unforgeability. We also modify schemes proposed by Mu & Varadharajan [18] and Gupta et al [11] to achieve formally provable security. We show that these modified schemes provide confidentiality against chosen ciphertext attack and unforgeability against chosen message attack.