分层的基于身份的动态门限签名方案

提出了一个分层的基于身份的动态门限签名方案.方案具有分层的PKG结构，低层PKG可以分担高层PKG的秘密信息产生和身份认证的任务；同时具有动态安全的特性，将签名的整个生命周期分成若干时间段，每个时间段都对密钥份额进行更新，更新后的份额重构的密钥保持不变.使用了离散对数相等的知识证明协议，以保证部分签名的正确性，并证明了方案的正确性、不可伪造性和鲁棒性.给出了方案的一些扩展.

Hierarchical ID-based proactive threshold signature scheme

A hierarchical ID-based proactive threshold signature scheme is presented. The scheme has the structure of hierarchical PKGs, so a lower-level PKG can share the workload of secret information generation and identity authentication with a higherlevel PKG. At the same time the scheme has the property of proactive security, that is, the whole lifetime of signature is divided into several time periods, and the shares of private key need to be, renewed in each time period. However, new shares can construct the same private key as old shares. We assure the correctness of part signatures by the knowledge proof protocol of discrete logarithm equality, and then prove that our scheme is correct, non-forgeable and robust. Finally, we give some extensions of this scheme.