A certificateless threshold public key encryption scheme

The decryption participant’s private key share for decryption is delegated by key generation center in the threshold IBE scheme.However,a key generation center which is absolutely trustworthy does not exist.So the author presents a certificateless threshold public key encryption scheme.Collaborating with an administrator,the decryption participant generates his whole private key share for decryption in the scheme.The administrator does not know the decryption participant’s private key share for decryption.Making use of q-SDH assumption,the author constructs a certificateless threshold public key encryption scheme.The security of the scheme is eventually reduced to the solving of Decisional Bilinear Diffie-Hellman problem.Moreover,the scheme is secure under the chosen ciphertext attack in the standard model.     

基于身份不可授权的强指定验证者盲签名

在盲签名方案中,消息和签名结果对签名人是不可见的.在不可授权强指定验证者签名中,只有指定验证者才能验证签名的有效性,而且其签名是不可授权的.设计了一种高效的身份基不可授权强指定验证者盲签名方案.分析结果表明,设计的方案不但是安全的,而且其效率也非常高.     

公平的基于身份的有向签名方案

 为了保护签名接收者的隐私,有向签名方案要求签名的验证必须得到接收者或签名者的合作.利用椭圆曲线上双线性映射的基于身份的密码体制,提出了一个公平的基于身份的有向签名方案.当签名者与验证者发生争议时,在二者的协助下,可信第三方能够进行公开验证签名.结果的分析表明,所提方案与同类方案相比签名长度更短并且通信代价更小.     

一种适用于基于身份的认证密钥协商的逆向防火墙协议

基于身份的认证密钥协商允许两方或者多方在不安全信道上建立安全的会话密钥。目前的认证密钥协商协议无法抵抗导致随机数泄露的后门攻击,比如已知特定于会话的临时攻击。基于此,我们设计了一种适用于基于身份的两方认证密钥协商的逆向防火墙协议。该协议在随机预言机模型下是安全的,能够抵抗强的临时会话秘密值泄露攻击,提供了消息抗泄露性。同时该协议不使用双线性对,节省了系统运行时间。最后,利用JPBC库实现了该协议。实验结果表明了该协议与同类型的协议相比,具有较小的带宽和较短的运行时间,十分适合应用于资源受限的系统中。     

Improvement of Identity-Based Threshold Proxy Signature Scheme with Known Signors

In 2006, Bao et al proposed an identlty-based threshold proxy signature scheme with known signers. In this paper, we show that Bao et al＇s scheme is vulnerable to the forgery attack. An adversary can forge a valid threshold proxy signature for any message with knowing a previously valid threshold proxy signature. In addition, their scheme also suffers from the weakness that the proxy signers might change the threshold value. That is, the proxy signers can arbitrarily modify the threshold strategy without being detected by the original signer or verifiers, which might violate the original signer＇s intent. Furthermore, we propose an improved scheme that remedies the weaknesses of Bao et al＇s scheme. The improved scheme satisfies all secure requirements for threshold proxy signature.     

一种安全可追责的基于身份密码方案

可追责的基于身份密码体制可以缓解基于身份密码体制的密钥托管问题：仲裁者根据获取的非法私钥判断其是否由私钥生成器恶意生成。本文针对一种可行的可追责的基于身份密码方案,将其中的零知识证明改为用双线性对运算实现;以此为基础,结合一次性签名方案提出一种具有IND—slD—CCA安全性的可追责的基于身份密码方案,并给出相关证明。     

An Identity-Based Strong Designated Verifier Proxy Signature Scheme

0 IntroductionIn 1996 ,Jakobsson, Sako and Impagliazzo introduced anew pri mitive called designated verifier proofs[1]. Suchproofs enable a prover Signy to designate who will be con-vinced by a proof .Furthermore,Jakobsson,Sako and Impa-gliazzo proposed a designated verifier signature. Designatedverifier signatures provide authentication of a message, with-out having the non-repudiation property of traditional signa-tures . They convince one-and only one-specified recipient thatthey are va…     

基于身份的可认证盲签名协议

提出了一个基于椭圆曲线双射对性质实现的、基于身份的具有可相互认证功能的盲签名协议.该协议把对用户身份的认证和对机构的认证融合到一个盲签名协议中,不仅避免了盲签名应用系统中对用户身份的额外认证,还使得应用系统的整体工作效率大大提高,有效地避免了盲签名系统在实际应用中同其他认证系统协同工作时可能出现的一些潜在的不安全问题.协议具有强不可伪造性和强不可否认性.     

Feasibility analysis of two identity-based proxy ring signature schemes

Recently, proxy ring signature schemes have been shown to be useful in various applications, such as electronic polling, electronic payment, etc. Although many proxy ring signature schemes have been pro-posed, there are only two identity-based proxy ring signature schemes have been proposed until now, i. e., Cheng＇s scheme and Lang＇s scheme. It＇s unlucky that the two identity-based proxy ring signature schemes are unfeasible. This paper points out the reasons why the two identity-based proxy ring signature schemes are unfeasible. In order to design feasible and efficient identity-based proxy ring signature schemes from bilinear pairings, we have to search for other methods.     

基于身份的多接收者的代理签密方案

利用双线性对提出一种基于身份的多接收者的代理签密方案,为电子政务和电子商务中具有多名合法接收者的签密问题提供了解决途径.此方案既保持了基于身份加密的优点,又具有可公开验证性和签名多向性,只有签密者认为合法的多名接收者才能各自独立从签密文中恢复消息,且安全性好.该方案具有很高的执行效率,签密过程只需1次双线性对运算,接收者人数越多,其效率的优势会越加明显.