Cut-and-Choose双向不经意传输

不经意传输作为现代密码学的一个基本工具,在安全协议的研究中起着重要作用.近年来,许多功能性更强的不经意传输变种被提出,以适应不同的需求和环境.提出一个新的不经意传输变种,称为cut-and-choose双向不经意传输;基于同态加密给出该原语的一轮高效协议构造,且在半诚实模型下形式化证明该协议的安全性.将cut-and-choose双向不经意传输运用到基于cut-and-choose技术的安全协议(尤其是安全两方计算)中,可以更具模块化地描述协议高层框架,降低协议交互轮数.此外,作为信息安全领域的一个底层基本工具,该原语本身也具有独立的研究意义.     

Secure linear system computation in the presence of malicious adversaries

In this paper,we study the system of linear equation problems in the two-party computation setting.Consider that P1 holds an m×m matrix M1 and an m-dimensional column vector B1.Similarly,P2holds M2 and B2.Via executing a secure linear system computation,P1 gets the output x(or⊥)conditioned on(M1+M2)x=(B1+B2),and the rank of matrix M1+M2,while P2 gets nothing.This also can be used to settle other cooperative linear system problems.We firstly design an efficient protocol to solve this problem in the presence of malicious adversaries,then propose a simple way to modify our protocol for having a precise functionality,in which the rank of matrix M1+M2 is not necessary.We note that our protocol is more practical than these existing malicious secure protocols.We also give comparisons with other protocols and extensions to similar functions.