标准模型下安全且高效的无证书签名方案研究

发布时间：2018-06-20 09:52

本文选题：无证书签名 + 密钥托管　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：近年来,无证书公钥密码体制由于其既不需要负担繁重的公钥证书管理又能够很好的解决基于身份公钥密码体制中的密钥托管问题而受到了学者的广泛关注。但是现有的关于无证书公钥密码体制的方案还存在一些问题。首先现有的大部分方案设计都是基于随机预言模型,而随机预言模型是一个理想的模型,并不适合于实际运用。其次,因为无证书密码体制中没有证书绑定用户的公钥并且用户的部分私钥是由KGC(密钥生成中心)产生,所以此类方案极易受到公钥替换攻击和不诚信KGC攻击。最后,大部分方案中KGC的信任等级只能达到了M.Girault信任等级定义中的等级2(KGC即使无法获得用户的私钥也能够伪装成任何用户进行非法操作)。本文主要针对以上问题进行研究,具体工作成果如下。1.对现有的在标准模型下的算法模型进行研究,发现基于该模型设计出的方案只能达到M. Girault信任等级定义中的等级2(KGC即使无法获得用户的私钥也能够伪装成任何用户进行非法操作),因此该模型是不安全的,本文对该模型进行改进使得方案中KGC的信任等级达到3,在此信任等级下KGC的任何伪装活动都能够被发现,从而削弱了方案中对KGC的信任依赖。2.对2012年Yu等人提出的在标准模型下的无证书公钥签名方案进行分析。通过分析推导出该方案中存在的问题,并且通过具体的攻击得出该方案无法抵御公钥替换攻击和不诚信KGC攻击。3.基于schnorr签名算法设计出在标准模型下安全且高效的无证书签名方案。并且通过严密的理论知识证明该方案能够抵御公钥替换攻击和不诚信KGC攻击。除此之外,根据M. Girault的信任等级定义,该方案能够达到信任等级3。
[Abstract]:In recent years, the certificateless public key cryptosystem has attracted wide attention because it can solve the key escrow problem in the identity-based public key cryptosystem because it does not have to bear the heavy burden of the public key certificate management and can solve the problem of key escrow in the identity-based public key cryptosystem. However, there are still some problems in the existing scheme of certificate-free public key cryptosystem. Firstly, most of the existing schemes are based on stochastic prophecy model, which is an ideal model and is not suitable for practical application. Secondly, because there is no certificate bound user's public key in the certificate free cryptosystem and part of the user's private key is generated by KGC (key Generation Center), this kind of scheme is vulnerable to public key replacement attack and dishonest KGC attack. Finally, the trust level of KGC in most schemes can only reach the level 2KGC in the definition of trust level of M. Girault, even if the private key of the user cannot be obtained, the KGC can still pretend to operate illegally by any user. This paper mainly aims at the above question carries on the research, the concrete work result is as follows. 1. The existing algorithm model under the standard model is studied. It is found that the scheme based on this model can only reach the level 2KGC in the definition of M.Girault trust level, even if the private key of the user can not be obtained, it can still be disguised as any user to carry out illegal operation, so the model is not safe. In this paper, the model is improved so that the trust level of KGC in the scheme reaches 3, under which any camouflage activities of KGC can be found, which weakens the trust dependency of KGC in the scheme. This paper analyzes the certificate-free public key signature scheme proposed by Yu et al in 2012 under the standard model. By analyzing and deducing the problems in the scheme, it is concluded that the scheme can not resist the public key substitution attack and the dishonest KGC attack. Based on the schnorr signature algorithm, a secure and efficient certificate free signature scheme is designed under the standard model. It is proved that the scheme can resist public key substitution attack and dishonest KGC attack through rigorous theoretical knowledge. In addition, according to M.Girault 's definition of trust level, the scheme can achieve trust level 3.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN918.91

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