基于身份的可快速撤销代理权的代理签密方案

An ID-based Proxy Signcryption Scheme with Fast Revocation

在代理签密方案中,一个被指定的代理签密人可以代表原始签密人生成有效的代理签密。然而,现有的代理签密方案都没有解决代理撤销问题,即如何收回代理签密人的签密权利。本文基于双线性对,提出了一个新的基于身份的代理签密方案,所提方案引入一个安全中介SEM,其作用是:帮助合法的代理签密人生成有效的代理签密;监督代理签密人是否按照授权证书的规定签名;检查代理签密人的签密权利是否被撤销。新方案不仅满足代理签密方案的所有安全要求,而且代理签密人只有与SEM合作才能生成有效的代理签密,使得方案具有快速撤销的功能。

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.