隐私是社会各界关心的热点问题，现代密码技术是实现隐私保护的重要工具之一。本项目结合实际应用对安全隐私的要求，研究基于属性签名与电子现金两类具有隐私保护功能的密码方案。项目的研究内容包括(1)事件关联的基于属性签名：在不泄露用户隐私信息的前提下关联同一个用户在一个事件中的多个基于属性签名；(2)支持双向隐私保护的电子现金：同时保护付款人隐私与收款人隐私的电子现金系统；(3)标准模型下安全的高效可分电子现金：提高标准模型下安全可分电子现金的实用性。课题的研究成果将进一步丰富隐私保护密码方案的设计，为保障网络用户的合法隐私权利提供理论支撑。

Privacy is of great concern to all sectors of our society, and modern cryptography is one of the key tools for privacy protection. Motivated by the needs from practical applications, this project studies two privacy protection cryptographic schemes: Attribute-based Signatures and Electronic Cash. This is carried out by investigating three specific issues (1) Event-Linkable Attributed-based Signatures: Link two or more attribute-based signatures from the same user in the same event without compromising the user privacy;(2) Electronic Cash with Two-Way Privacy Protection: Provide privacy protection for both the payer and the payee; and (3) Efficient Secure Divisible Electronic Cash in the Standard Model: Improve the practicality of divisible electronic cash in the standard model. The research deliveries will bring new designs of privacy protection cryptographic schemes and provide theoretic support towards the legal privacy protection of network users.