安全的多方计算理论及其应用

The project Secure Multi-Party Computation and its Applications was carried out from January of 2000 to December of 2002, ca. 20 faculty members and graduates students took part in this project. In the last 3 years there are more than 40 papers was published in this field.The problem of secure multi-party computation is fundamental in cryptography. In particular, almost any known cryptographic setting and problem can be viewed as a special case of this general problem (e.g., encryption, authentication, commitment, signatures, zero-knowledge, and many others). Thus secure multi-party computation may serve as a general, uniform paradigm for the study of most of cryptography. Furthermore, understanding secure multi-party computation is fundamental in study of distributed systems in general. Consequently, secure multi-party computation has been a hot subject in the field of cryptography and information security.Our summarized the current research status of multiparty computation protocols, introduced the four types of multiparty computation protocols and analyzed them. The four types of multiparty computation protocols are: multiparty computation protocol based on OT (Oblivious Transfer), multiparty computation protocol based on VSS (Verifiable Secret Sharing), multiparty computation protocol based on threshold homomorphic encryption and multiparty computation protocol based on Mix-Match..On basis of the analysis of the strengths and shortcomings of the protocols, we improved on the four types of multiparty computation protocols. The improvements are: Multiparty computation protocol based on OT; Multiparty computation protocol based on VSS; Multiparty computation protocol based on threshold homomorphic encryption; Multiparty computation protocol based on Mix-Match. In addition, based on the analysis of the character of the existed protocols, we provided a new multiparty computation protocol. This outstanding character of this protocol is: It's easy to compute the multiplication and reversion operation while it's complex to calculate addition operation. Another strength of this protocol is that it has no limit on the number of inputs to an operation, it can realize entities multiplication operation and addition operation.

安全多方计算理论是密码学中一个崭新的热门领域，它主要讨论一组非互相信任的人群如何通过网络计算,求出给定的函数值，而不泄露每一方的输入[自变量]。.安全多方计算是许多密码学问的基础。对多方计算的深入研究，有助于从更高层面认识、理解密码理论，对网络环境的信息安全有极其重要的指导意义。.