基于广播加密的多策略非对称叛逆者追踪方案

双线性映射叛逆者追踪方案不能抵抗叛逆者攻击，且计算量与用户数量相关，计算效率很低。为了减少计算量、存储量和通信量，提高安全性能，基于离散对数难题，提出多策略、多服务、非对称公钥叛逆者追踪方案，进行了安全性证明和效率分析。该方案通过改变门限值t实现了多策略广播，可灵活运用于不同的网络广播领域。分析表明，方案具有更高的计算效率和更短的密文长度，同时该方案被证明可实现面向多服务、抗共谋性、完全撤销性、完全可恢复性和黑盒追踪性。

A multi-policy asymmetric traitor tracing scheme based on broadcast encryption

It was found that the scheme could not resist collusion attack and is similar to most schemes, its efficiency is very low because of relating to the quantity of users. In order to improve safety performance and to reduce the amount of computation, storage, communication, based on discrete logarithm problem, a new multi-policy multi-service asymmetric public-key traitor tracing scheme is proposed. The new scheme can be used flexibly in all kinds of domain because multi-policy broadcast has been realized by using different threshold valuet. Compared to most typical schemes, the scheme has higher computation efficiency and shorter cipher text length, it also has stronger safety features since multi-service oriented, collusion resistance, full revocation, full recoverability, and black-box traceability can be realized.