An ID-based Proxy Signcryption Scheme with Fast Revocation
基于身份的可快速撤销代理权的代理签密方案

Proxy signcryption schemes allow an original signcrypter to delegate his signcryption rights to a proxy signcrypter. However, the existing proxy signcryption schemes have the defect that can not solve the proxy revocation problem, that is, how to revoke the delegated signcryption rights of a proxy signcrypter. Based on the bilinear pairings, a new identity-based proxy signcryption scheme is proposed in this paper. A SEcurity Mediator (SEM) is introduced in the scheme to help a proxy signcrypter to generate valid proxy signcryptions, to examine whether a proxy signcrypter signcrypts messages according to the warrant, and to check the revocation of a proxy signcrypter. It is shown that the proposed scheme satisfies all the security requirements of a secure proxy signcryption scheme. Moreover, a proxy signcrypter must cooperate with the SEM to generate a valid proxy signcryption, which makes the new scheme has an effective and fast proxy revocation.