RPCAE: a novel revocable proxy convertible authenticated encryption scheme

摘要

Convertible authenticated encryption schemes allow a signer to produce an authenticated ciphertext and only a designated recipient can verify its signature. Such schemes also provide an additional signature conversion mechanism to convince anyone of signer's dishonesty when a later dispute occurs. Proxy signature schemes allow an authorized proxy signer to generate proxy signatures on behalf of the original signer according to the predefined signing policy. In this paper, we elaborate on the merits of both systems to propose the first novel Revocable Proxy Convertible Authenticated Encryption (RPCAE) scheme for confidential applications with proxy delegation. The revocation protocol is rather simple and incurs no extra computational efforts. Moreover, the IND-CCA2 and the EF-CMA security for the proposed scheme are also formally proved.