基于DC-net的会议室电子选举方案

提出了一种新的适用于小规模选举活动的电子选举方案,其最大特点是能够提供无条件的完美选票秘密性保障。方案具有自计票功能,能够实现公平性和可验证性。敌手对选举结果的破坏等同于解离散对数问题。该方案建立在DC-net匿名广播协议基础之上,其安全性不依赖于任何信任中心,但需假定任意投票者之间存在秘密信道。     

选择密文安全的可验证Mix-Net协议

A CCA-secure verifiable Mix-Net protocol with provable security was proposed.The protocol was based on Wikstr?m’s Mix-Net and improves its security by introducing an improved key generation algorithm and a new method for constructing proof of secret shuffling.Without revealing the correspondence between inputs and outputs,proposed protocol enables everyone to verify the correctness of output plaintexts through checking evidences broadcasted by each server.Thus,it satisfies public verifiability.Any sender can trace and examine the processing procedure of its ciphertext.Thus,proposed protocol satisfies sender verifiability.It is prored to be CCA-secure under the assumption of random oracle.Compared with previous mix-net schemes which are CCA-secure,proposed protocol does not require any trusted center,and incurs fewer interactions between servers which also resulting in a lower computation and communication complexity.Hence,the protocol is an ideal cryptographic tool for constructing secure electronic election protocol.     

高效的基于混合加密的乐观Mix-net协议

提出了一种高效的基于混合加密算法的Mix-net协议。正常情况下,当所有Mix服务器都忠实地执行协议时,其运算速度优于其他所有已知的具有公开可验证性的Mix-net。采用一种“乐观的”、基于散列运算的方法验证混洗过程的正确性,避免了构造复杂的、耗时的零知识证明,因此获得了速度上的提升。只用两轮逐元素的测试过程确保消息未被恶意服务器篡改,并且测试中仅涉及低代价的散列运算。公钥加密和对称密钥加密的有效结合也加速了混洗。这些优化措施使单个Mix服务器的运算量几乎和服务器数目无关,除了少量可忽略的计算任务。此外,任何人都可以通过少量的指数运算快速验证输出结果的正确性。方案也满足健壮性。这些特点使该方案非常适合用在大规模的电子选举中。