基于ECC的可转换签密及其门限共享验证方案

A Convertible Signcryption and Threshold Shared Verification Scheme Based on ECC

本文首先基于椭圆曲线密码体制，提出了一个具有可转换功能的签密方案。该方案能抵抗已知明文攻击，并克服了H—C方案和W-B方案不满足语义安全的不足。由于方案是基于椭圆曲线密码体制建立的，因而它的计算代价和通信代价均很小。基于该签密方案，构建出了一个（t，n）门限共享验证签密方案，其优点在于能防止可信中心的欺诈，并在共享验证和消息恢复阶段，提出了一种能防止验证成员提供假秘密份额进行欺诈的方法。

Firstly, this paper presents a convertible signcryption scheme based on elliptic curve cryptosystem. Our scheme can stand against the known-plaintext attack, and overcome the weaknesses that the semantic security t of the message cannot be provided in H-C and W-B schemes. Because our scheme is built based on ECC, its computational cost and communication cost are lower, Based on the proposed signcryption scheme, we design a threshold signcryption scheme with （t, n） shared verification. This threshold scheme can prevent the cheating of trusted center, In the shared verification and message recovery phase, we propose a method to prevent the cheating that the verification member forges secret share.