【作者】 徐晓琴；

【导师】 卢辉斌；

【作者基本信息】 燕山大学 ， 信号与信息处理， 2009， 硕士

【摘要】 信息的数字化导致其很容易遭受窃听、截取、修改、伪造、重放等来自各方面的各种攻击手段的攻击。因此如何保证信息的保密性、完整性、可用性、可控性和可审查性已成为信息安全的重要课题。为了实现信息的完整性保护,根据不同的情况可以采用的方式有:使用密码技术实施数字签名、对信息进行完整性校验、对用户进行身份认证等。基于身份的密码系统有其固有的缺陷,如密钥托管等。密钥托管问题会使得一个不诚实的PKG(Private Key Generator)伪造用户的签名,从而导致即使PKG是诚实的情况下,用户同样会对自己的签名进行抵赖。为了解决这一问题,本文采用双线性对叙述了一种无可信PKG的基于身份的签名方案。PKG在本文中并没有被删除,它依然必须为用户生成私钥,但是用户可以控制自己的私钥而不被PKG知晓,因为生成的私钥中包含用户自己选择的私钥。如果不诚实的PKG冒充用户对某个消息进行签名,那么用户可以提交一些自己掌握的信息来证明PKG的不诚实行为。无证书公钥密码体制消除了基于身份公钥密码体制中固有的密钥托管问题,同时还保持了基于身份密码体制的优点。本文在随机语言模型下,在强k-CAA和Inv-CDHP假设下,利用了一种可证明安全的高效无证书签名方案,验证了其方案的签名长度为160 bits。在比较身份的公钥密码系统(ID-PKC)和无证书公钥密码系统(CL-PKC)各自优缺点的基础上,介绍了无证书的认证在混合P2P中的应用。该方案克服了P2P网络中PKI繁琐的证书管理和ID-PKC的密钥托管等问题,提高了双向认证和密钥协商的速度,具有较高的效率,能较好地解决混合P2P网络的安全问题。更多还原

【Abstract】 Digital stream can be easily wiretapped, intercepted, modified, forged, and replayed. Therefore, the most importent task for information security is how to keep confidentiality, integrity, availability, controllability, and accountability for digital information. As the case may be, we can adopt different way to protect the information’s integrity, such as signature, integrity check, and authentication on identity.Key escrow is an inherent disadvantage for traditional ID-based cryptosystem, for example, the dishonest PKG can forge the signature of any user on the other hand. The user can deny the signature actually signed by him/herself. To avoid the key escrow problem, we describe an ID-based signature scheme without trusted Private Key Generator (PKG). There still needs a PKG in our scheme to generate the private key of the user, but the user can keep their private key secret from knowing by PKG, because the private key embeds some particular information chosen by the user. If the dishonest PKG impersonate an honest user to sign a message, the user can provide this particular information to verify the dishonest of the PKG.Certificateless Public Key Cryptography (CL-PKC) eliminates the inherent key escrow problem of ID-based cryptography, while preserving the attractive advantage of cryptography which dispenses with certificates of traditional Public Key Cryptography (PKC). In this paper, we make use of a short CLS scheme that is proved to be secure in the random oracle model under the hardness assumption of k-CAA and Inv-CDHP,validate the length of our scheme is 160 bits. Based on the respective analysis of the advantages and disadvanrages of identity-based cryptography (ID-PKC) and certificateless public key cryptography (CL-PKC) introduces a certificateless authentication in hybrid P2P network. The scheme overcomes the problem of complicated management of PKI certificates and the key escrow of ID-PKC in P2P network.It speeds up the time of bidirectional authenticated and key agreement protocols,proved to be more efficient,and can better solve the security problems in the hybrid P2P network.更多还原