基于安全多方计算的公钥密码构造

Due to the powerful functionality and the rich construction, secure multi-party computation(SMC) is a very promising building-block of cryptography, which is well worth studying. Nevertheless, now there are few researches on basic protocols of SMC, especially the construction of public key cryptography in the context of cloud computing. Based on the concept of SMC, this project tries to explore the new construction of public key cryptography and studies its two related aspects: (1) unencrypted methodology for SMC, and (2) embedding MPC protocol with algebraic function into public key encryption. The objectives of this project are listed in the following: (1) to design MPC protocol with unencrypted method, and (2) to realize the secure cloud data sharing without a trusted third party, fully privacy-preserving, and algebraic structure’s access control. The innovation of this project is to apply SMC to constructing the public cryptography served in the cloud computation, and further to solve the existed problems in secure cloud data sharing, which will provide theoretical basis and technical supports for the development of cloud computing in our country.

安全多方计算的功能强大，构造力丰富，是十分有潜力的密码学构造工具，值得投入大量精力研究。但目前安全多方计算的一些基础协议研究较少，尤其以云计算为应用背景的公钥密码构造更少。本课题拟以安全多方计算思想，开拓公钥密钥的新构造，研究与之相关的两个内容：(1)非加密方法的安全多方计算；(2)将具有有代数关系的安全多方计算协议嵌入公钥加密。研究目标：(1)设计非加密安全多方计算基础协议；(2)实现无可信第三方、全隐私保护、代数访问结构的云数据安全共享。本课题的创新之处是利用安全多方计算特性构造以云计算为应用背景的公钥密码，解决云数据安全共享存在的问题，从而为我国云计算发展提供了理论基础和技术保障。

安全多方计算和公钥加密的同性是：都至少涉及两方参与计算，都需要保护数据的隐私。不同的是，公钥加密一般只涉及两方，但如果只研究安全两方计算，即参与者只有两方，那么安全多方计算就可蜕变为公钥加密。本项目以安全多方计算、公钥加密两种密码原语为研究实例，具体研究了：1) 非加密方法安全多方计算协议构造；2) 利用安全两方计算技巧设计公钥密码。针对这2个研究内容，我们将安全多方计算和公钥加密的技巧相互借鉴，深入分析了国内外现有的方案，设计出新型的安全多方计算协议和公钥密码方案，在高质量的国际、国内期刊和会议上发表了相应的论文。本项目从安全多方计算的角度出发，借助安全多方计算的诸多技巧设计公钥加密，这为构造公钥密钥提供了一种全新的途径，因此对公钥密码发展具有新颖而重要的意义。