An efficient certificateless undeniable signature scheme

Certificateless cryptography addresses the private key escrow problem in identity-based systems, while overcoming the costly issues in traditional public key cryptography. Undeniable signature schemes were proposed with the aim of limiting the public verifiability of ordinary digital signatures. The first certificateless undeniable signature scheme was put forth by Duan. The proposed scheme can be considered as the certificateless version of the identity-based undeniable signature scheme which was introduced by Libert and Quisquater. In this paper, we propose a new scheme which is much more efficient comparing to Duan's scheme. Our scheme requires only one pairing evaluation for signature generation and provides more efficient confirmation and disavowal protocols for both the signer and the verifier. We also prove the security of our scheme in the strong security model based on the intractability of some well-known pairing-based assumptions in the random oracle model.     

Efficient and provably-secure certificateless short signature scheme from bilinear pairings

Certificateless public key cryptography is a recently proposed attractive paradigm which combines advantages of both certificate-based and ID-based public key cryptosystems as it avoids usage of certificates and does not suffer from key escrow. In this paper, we present a certificateless signature (CLS) scheme that is proved to be secure in the random oracle model under the hardness assumptions of k-CAA and Inv-CDHP. Our scheme upholds all desirable properties of previously proposed CLS schemes, and requires general cryptographic hash functions instead of the MapToPoint hash function which is inefficient. Furthermore, our scheme is significantly more efficient than all known CLS schemes, and the size of signatures generated by our scheme is approximate 160 bits, which is the shortest certificateless signatures so far. So it can be used widely, especially in low-bandwidth communication environments.     

一种新的无证书的代理环签名方案

在不失基于身份的公钥体制密钥管理简单的前提下,无证书公钥密码体制克服了其所固有的密钥托管缺陷,简化了传统公钥体制负担过重的密钥管理问题。鉴于无证书密码体制的优点,结合代理签名和环签名的优点,提出了一种新的高效的无证书的代理环签名方案。该方案没有密钥的托管问题,也不需要管理证书,并且满足代理环签名方案所有的安全性要求。与现有方案相比,新方案的有效性显著提高。     

基于RSA的无证书广播多重代理签名方案

由于无证书密码体制可以避免证书管理和密钥托管问题,近年来成为密码学界研究的热点之一,很多无证书代理签名方案（CLPS）被提出。针对目前很多无证书代理签名方案都是基于双线性对设计的,具有效率低和应用中实现困难的问题,本文提出一种基于RSA的无证书广播多重代理签名方案。基于RSA问题,分析了方案的安全性,与已有方案的效率相比,新方案的效率更高。      

A new provably secure certificateless short signature scheme

Certificateless public key cryptography simplifies the complex certificate management in the traditional public key cryptography and resolves the key escrow problem in identity-based cryptography. In 2007, Huang et al. revisited the security models of certificateless signature scheme. They classified adversaries according to their attack power into normal, strong, and super adversaries (ordered by their attack power). Recently, Du and Wen proposed a short certificateless signature scheme and presented that their scheme is secure against the strong adversary in the random oracle model. In this paper, we show that their short signature scheme is insecure against the strong adversary. We then propose a new short certificateless signature scheme which is secure against the super adversary. Our scheme is the first certificateless signature scheme which satisfies both the strongest security level and the shortest signature length.     

一个可证明安全的无证书盲环签名方案

为了设计一种有效的盲环签名方案, 同时克服公钥证书密码体制中的复杂证书管理以及基于身份密码体制中的密钥托管问题, 将盲环签名和无证书密码体制相结合, 充分利用两者的优势, 并通过使用双线性对技术, 在随机预言模型下基于k-碰撞攻击算法(k-CAA)困难问题和修改的逆计算Diffie-Hellman(mICDH)困难问题, 提出了一种有效的无证书盲环签名方案。最后, 对方案的正确性和安全性进行了分析, 证明了该方案满足适应性选择消息攻击下的存在不可伪造性、盲性和无条件匿名性。     

一个无证书代理签名方案的安全性分析

无证书公钥密码体制消除了公钥基础设施中的证书,同时解决了基于身份的公钥密码体制中的密钥托管问题.最近,樊睿等人在一个无证书签名方案的基础上提出了一个无证书代理签名方案,并声称该方案满足无证书代理签名方案的所有安全性质.可是,通过对该无证书代理签名方案进行分析,证明了该方案对于无证书密码体制中两种类型的攻击即公钥替换攻击和恶意KGC(Key Generating Centre)攻击都是不安全的.给出了攻击方法,分析了其中的原因并提出了相应的防止措施.     

安全的无证书聚合签名方案

无证书密码系统既解决了密钥托管问题,又不涉及公钥证书;而聚合签名可以有效地减少计算代价和通信开销.结合二者的优点构造无证书聚合签名是很有意义的.尽管无证书聚合签名方案的构造已经取得了重要进展,但是现有的方案仍然不能同时达到既可抵抗两类超级攻击者又具有运算的高效性.使用双线性映射并引入状态信息来设计具有强安全性的无证书聚合签名方案.在随机预言模型中,该状态信息被用于嵌入给定困难问题的部分信息.结果显示,该方案的安全性基于计算Diffie-Hellman问题的困难性并可以抵抗超级攻击者的攻击.同时,由于充分利用公开信息和双线性映射的性质,它在个体签名和聚合签名验证过程只需4个双线性映射.另外,在该方案中,用户知道状态信息后可独立完成个体签名而无需交换信息,所以它允许用户动态地加入聚合签名.故它可应用于多对一的通信系统中.     

Delegation of signing rights using certificateless proxy signatures

A proxy signature scheme allows a proxy signer to sign messages on behalf of an original signer within a given context. It has lots of practical applications in distributed systems, grid computing, mobile agent applications, distributed shared object systems, global distribution networks, and mobile communications. In the last years, fruitful achievements have been seen in certificateless public key cryptography which has the advantages of no certificate management and no key escrow compared with traditional public key cryptography and identity-based public key cryptography respectively. However, the existing certificateless proxy signature schemes is either insecure or without formal security analysis. In this paper, we formalize the security model of certificateless proxy signature schemes and propose a provably secure certificateless proxy signature scheme with formal security proof under the computational Diffie–Hellman assumption.     

可证安全的无证书群签名方案

提出一个安全有效的无证书群签名方案。该方案满足群签名的各种安全性要求,还允许用户动态地加入与离开且不需更新群公钥和其他群成员的签名私钥。群签名的长度不依赖于群成员的数目。它的安全性建立在计算Differ-Hellman问题的困难性之上。     

Certificateless multi-proxy signature

Multi-proxy signature is a scheme that an original signer authorizes a proxy group as his proxy agent and later only the cooperation of all proxy signers in the proxy group could sign messages on behalf of the original signer. To our best knowledge, most of the existing multi-proxy signature schemes are proposed in public key infrastructure or identity-based setting. However, due to avoiding the inherent escrow problem of identity-based cryptography and yet not requiring certificates to guarantee the authenticity of public keys, certificateless public key cryptography has become an attractive paradigm on which many cryptographical primitives are based. In this paper, a generic construction and a formal security model of certificateless multi-proxy signature (CLMPS) are firstly defined. A concrete CLMPS scheme is also proposed, which is proven to be existentially unforgeable against adaptively chosen warrant attacks and chosen message and identity attacks in the random oracle model under the computational Diffie-Hellman assumption.     

可证安全的无证书代理签名方案

研究在新提出的无证书公钥密码系统下的代理签名问题,给出了无证书代理签名方案非常强的安全模型.该安全模型下的攻击者是能力最强的超级类型I 和类型II 攻击者.同时,利用双线性映射设计了一个高效的无证书代理签名方案.其安全性基于计算Diffie-Hellman 问题的困难性,并在此安全模型下给出正式的安全证明. 鉴于方案的安全、高效和无证书管理的优点,它可广泛应用于电子商务、移动代理系统等方面.     

A new certificateless aggregate signature scheme

Aggregate signatures are useful in special areas where the signatures on many different messages generated by many different users need to be compressed. In this paper, we study aggregate signatures in certificateless public key settings. We first present the notion and security model of certificateless aggregate signature schemes. Then we give an efficient certificateless aggregate signature scheme. Our scheme is existentially unforgeable under adaptive chosen-message attacks assuming the computational Diffie–Hellman problem is hard.     

新的无证书代理盲签名方案

无证书公钥密码学既不存在传统的公钥密码系统的证书管理耗费,也不存在基于身份的密码系统中的密钥托管问题,安全且高效。研究了代理盲签名方案的构造和应用,发现现有的无证书代理盲签名方案较少,而在无证书密码系统中研究代理盲签名会更容易满足其在电子投票、电子银行等应用领域中对安全性和高效性的要求。 基于双线性对知识和离散对数困难问题,提出了一种无证书代理盲签名方案,该方案满足盲性、不可伪造性、可鉴别性、不可否认性等性质。     

Efficient many-to-one authentication with certificateless aggregate signatures

Aggregate signatures allow an efficient algorithm to aggregate n signatures of n distinct messages from n different users into one single signature. The resulting aggregate signature can convince a verifier that the n users did indeed sign the n messages. This feature is very attractive for authentications in bandwidth-limited applications such as reverse multicasts and senor networks. Certificateless public key cryptography enables a similar functionality of public key infrastructure (PKI) and identity (ID) based cryptography without suffering from complicated certificate management in PKI or secret key escrow problem in ID-based cryptography. In this paper, we present a new efficient certificateless aggregate signature scheme which has the advantages of both aggregate signatures and certificateless cryptography. The scheme is proven existentially unforgeable against adaptive chosen-message attacks under the standard computational Diffie–Hellman assumption. Our scheme is also very efficient in both communication and computation and the proposal is practical for many-to-one authentication.     

一种公平的无证书电子现金方案

在跨域和跨组织的电子商务应用中,基于公钥基础设施的密码技术存在沉重的公钥证书管理负担,而基于身份的密码技术存在密钥托管问题,这些都制约了电子现金方案的进一步发展。而基于无证书的密码技术可以避免这些问题。提出了一种基于无证书的签名和认证密钥交换机制,分析了该机制的安全性。基于新的无证书签名和认证密钥交换机制,提出了一种新的电子现金方案。该方案满足电子现金的不可伪造性和不可重用性、用户匿名性以及电子商务交易的公平性。     

有效的无证书代理签名方案

利用双线性映射设计一个有效的无证书代理签名方案。在最强的安全模型下,方案给出了正式的安全证明。它的安全性基于计算Diffie-Hellman问题的困难性。分析显示新方案满足诸如可验证性、强不可否认性、强可识别性、防止签名滥用等安全性质。鉴于方案的安全、高效和无证书管理的优点,它可广泛应用于电子商务、移动代理系统等方面。     

新的无证书的代理签名方案

已有的代理签名方案,大多是基于证书的密码体制或者基于身份的密码体制提出的,都存在证书的管理问题或密钥的托管问题。基于无证书密码体制的优点,在无证书公钥密码体制的基础上提出了一种新的代理签名方案。分析表明, 该方案不需要证书的管理,也没有密钥的托管问题,满足代理签名所要求的所有性质,且在效率上优于已有的基于身份的代理签名方案。     

一类无证书签名方案的构造方法

无证书密码体制(CL-PKC)是一类新型公钥密码体制.它保持了基于身份的密码体制(ID-PKC)不需要使用公钥证书的优点,又较好地解决了基于身份的公钥体制所固有的密钥托管问题.对无证书体制下安全高效的签名方案的设计方法的研究是受到高度关注的研究课题.文中给出了一类无证书签名方案的构造方法,并在一个很强的安全模型下对用该方法所构造的方案的安全性进行了证明.文中对新构造的方案与已有的一些同类方案的性能进行了比较.结果显示新方案在整体性能上有一定的优势.