A GROUP-ORIENTED PROXY CMAE SCHEME WITH COMPUTATIONAL SECRECY

Abstract

This paper presents a group-oriented proxy convertible multi-authenticated encryption (CMAE) scheme for strengthening the gradually wide applications which have to simultaneously fulfill the security requirements of integrity, authentication, confidentiality and non-repudiation. The proposed scheme allows a group of original signers to delegate their signing power to an authorized person called proxy signer, such that the proxy signer can generate an authenticated ciphertext on behalf of the original group. Instead of anyone else, only a designated recipient can decrypt the ciphertext and verify its corresponding signature for the purpose of confidentiality. In case of a later dispute over repudiation, the designated recipient also has the ability to convert the multi-signature into an ordinary one for convincing anyone of the signer's dishonesty. Moreover, the computational secrecy ensures that the produced ciphertext is computationally indistinguishable with respect to two candidate messages.