基于多变量公钥密码体制的环签名变体方案

Variant Scheme of Ring Signature Based on Multivariate Public Key Cryptosystems

基于多元二次方(MQ)问题的多变量公钥密码体制是一种可以抵抗量子攻击的系统。分析基于多变量公钥密码体制的环签名方案,指出其存在密钥泄露和安全证明错误的问题。为解决上述问题,对环签名者和其他环成员采用不同的密钥构造方式,提出一种可证明安全的环签名变体方案。该方案最大程度地去除原方案对IP问题的依赖,使得方案的安全性直接规约于MQ问题,以提升安全性。在环签名的标准安全模型下,分别从正确性、匿名性和不可伪造性等方面对方案进行分析和安全性证明,结果表明,与原方案相比,该方案有较高的安全性。

Based on Multivariate Quadratic（MQ） problem,Multivariate Public Key Cryptosystems（MPKC） are regarded as systems resisting quantum attacks.This paper analyzes a ring signature scheme based on MQ and points out that there exist some issues such as secret key leakage and incorrect security proof.To solve these problems,this paper proposes a variant of ring signature scheme with provable security by applying different key generation methods to ring signer and the remaining ring members.The scheme removes the dependence on IP problem as much as possible,gaining higher security by direct reduction to MQ problem.This paper gives detailed analysis and security proof of the new scheme from the aspects of correctness,anonymity and unforgeability in the standard security model of ring signature.Compared with the original scheme,the scheme is more complete both in analysis and security proof.