一种基于DAA的强匿名性门限签名方案

针对目前大多数门限签名方案不能实现签名成员匿名或匿名效果比弱的问题,该文提出了一种带有子密钥分发中心的强匿名性(n, t)门限签名方案。方案主要基于可信计算组织在其v1.2标准中采用的直接匿名认证(Direct Anonymous Attestation, DAA)方案,以及零知识证明和Feldman门限秘密共享等技术实现。相较已有方案,该方案即使在签名验证者和子密钥分发中心串通的情况下,也能够实现子签名的不可追踪性,也即可确保子签名成员的强匿名性。分析显示,方案除具有强匿名性外还具备签名子密钥不可伪造、子签名可验证以及一定的鲁棒性等特征。该方案在匿名表决等一些对匿名性要求较高的场合中有着重大的应用价值。     

一种签名长度固定的基于身份的环签名方案

环签名作为一种匿名通信技术,可以使签名人具有匿名性。在以往提出的环签名方案中,签名长度与环成员个数成正比,这是环签名的一个公开问题。该文使用双线性对,并基于累加器技术,提出了一种签名长度固定的基于身份的环签名方案,并证明了其安全性。方案既能保证消息发送者的匿名性,又可使得到的签名长度与环成员个数无关,解决了环签名的公开问题。     

原始签名人匿名的代理环签名研究

环签名是一种新的匿名签名技术,能保证签名用户的无条件匿名性。代理环签名是将代理签名和环签名相结合产生的一种签名。已有的代理环签名方案都是利用环签名的思想实现代理签名人的身份匿名性,但原始签名人的身份始终是公开的。该文基于RSA问题的难解性提出了一种新的代理环签名方案,在保证代理签名人身份匿名性的同时,还能保证原始签名人身份匿名性,并证明该方案在随机预言模型下能抵抗适应性选择消息攻击。     

基于比特承诺的可撤销匿名电子检举系统

一个安全的电子检举系统必须满足检举人身份匿名性的要求,保证检举人的隐私,同时在必要的情况下,检举系统也能够提供匿名的撤销。Qiu等提出了一种基于群签名的可撤销匿名的电子检举系统,提供了可撤销的匿名检举,并满足一序列安全性要求,但基于群签名的方案对于大量群成员存在着无法避免的效率问题。文中基于比特承诺协议,提出了一种可撤销匿名的检举方案。该方案在提供了举报过程中对于举报者身份的匿名性的同时,对于可能的恶意举报,在电子检举中心（EIC）和可信第三方（TTP）的协作下,能够撤销匿名,追查责任人。该方案可适用于不同规模的使用人群。     

一种新型匿名认证方案的研究

为了克服现有可信平台认证方法的缺陷,提出了一种基于单项累加器的新型可信平台匿名认证方案,并构造了具体方法.新方案利用环签名技术的匿名性实现直接匿名认证,同时运用单向累加器技术将环签名成员信息累加,使得签名环长度固定,不会随着环规模增大而增大.验证时,有效降低了hash计算和加密、解密运算的次数,提高了认证的效率.通过与典型的环签名方案的比较,表明该方法所需的空间复杂度和时间复杂度更小,并弥补了传统环签名方案签名长度随环规模增大而增加的缺点,在保证安全性的前提下具有较高的实现效率.     

移动计算中基于椭圆曲线的匿名签名算法

移动代码(例如移动代理)在异地执行签名时往往不希望暴露其所有者的私有密钥,本文提出了一种基于椭圆曲线的移动代码匿名签名算法,依据该算法,移动代码所有者可以利用椭圆曲线根据自己的身份信息为移动代码生成一个认证矢量和一个临时性密钥对,并通过它们实现了移动代码匿名签名以及签名后的不可否认性.该算法除具有匿名性和不可否认性以外,还具有高效性、保密性和不可伪造性等特点,可广泛应用于各种具有代码移动特性的移动计算.     

无可信中心的门限追踪ad hoc网络匿名认证

为解决ad hoc网络中的匿名认证问题,将民主签名与无中心的秘密分享方案相结合,提出一种无可信中心的门限追踪ad hoc网络匿名认证方案。方案的无中心性、自组织性很好地满足了ad hoc网络的特征,从而解决了传统网络中匿名认证方案由于需要可信中心而不适合ad hoc网络的问题;方案中认证者的匿名性、可追踪性和完备性(不可冒充性)满足了匿名认证的安全需求。     

多样化的可控匿名通信系统

随着网络通信技术的发展,Tor匿名通信系统在得到广泛应用的同时暴露出匿名性较弱等不安全因素,针对上述问题,基于节点的区域管理策略提出一种多样化的可控匿名通信系统(DC-ACS),DC-ACS中多样化匿名链路建立机制根据用户需求选择相应区域的节点完成匿名通信链路的建立,同时基于行为信任的监控机制实现对用户恶意匿名行为的控制,并且保证了发送者和接收者对匿名链路入口节点和出口节点的匿名性。通过与Tor匿名通信系统的比较,DC-ACS在具有匿名性的同时,具有更高的安全性和抗攻击的能力,解决了Tor匿名通信系统所存在的安全隐患。     

一种基于群签名的分布式洋葱路由

洋葱路由技术是指一个在公用网络上广泛运用的基于P2P的匿名通信技术,它使得攻击者既不能进行窃听,也不能实施流量分析,实现了信息发送者和接收者的匿名性,也保护了信息内容本身的安全。针对当下洋葱路由实现的基本模型,结合群签名技术和分布式的概念,文中提出了一种基于群签名的分布式洋葱路由方案,并对其性能做了简单的分析,证明确实在路径的隐蔽性、系统的安全性等方面都有了较好的提升。     

可撤销匿名的电子检举系统

论文利用群签名技术,提出了一种可撤销匿名的检举系统,一方面,它能有效地保护检举人的隐私,另一方面,在电子检举中心的协助下,一个可信第三方（TTP）可撤销检举人的匿名性,因此可有效地防止诬告行为。本文述及的检举系统,适用于中小规模的群使用。     

Unconditionally Anonymous Ring and Mesh Signatures

We generalize the ring signature primitive into the more general notion of mesh signature. Ring signatures are anonymous signatures made by someone who wishes to hide in the anonymity of a larger crowd. All that the signer needs to assemble such a virtual crowd is her own private key and the public keys of the other members. The crowd composition is all that the verifier will be able to see. In a sense, a ring signature expresses an anonymous endorsement of a message by a disjunction of signers. Mesh signatures generalize this notion by allowing the combination of “atomic” (i.e., regular) signatures, by one or multiple signers from an arbitrary larger crowd, into virtually any monotone “endorsement formula” with much more expressive power than a simple disjunction. The verifier sees only that the endorsement is valid for the stated formula, not how the formula is satisfied. As a special case, mesh signatures extend the ring signature functionality to certificate chains. This is useful when the anonymity-seeking signer wishes to hide in a crowd comprising uncooperative people who do not even have a published signature verification key on record. We give an efficient linear-size construction based on bilinear maps in the common random string model. Our mesh signatures achieve everlasting perfect anonymity—an imperative for the archetypical whistle-blowing use case of ring signatures—and, as a special case, yield the first unconditionally anonymous ring signatures without random oracles or trusted setup authorities. Non-repudiation is achieved from a mild extension of the SDH assumption, named Poly-SDH, which we introduce and justify meticulously.     

An improved EAAP scheme for vehicular ad hoc networks

Recently, Maria Azees et al proposed an “EAAP: efficient anonymous authentication with conditional privacy‐preserving scheme for Vehicular Ad Hoc Networks.” Their scheme is mainly to solve the problem of high computation time of anonymous certificate and signature authentication, as well as the tracking problem of malicious vehicles. However, some improvements are needed in the protection of anonymous identity and the effective tracking of malicious vehicles. In this paper, our scheme realizes mutual authentication between OBU and RSU, and the RSU is authenticated without using certificate. In order to prevent the anonymous identity of the vehicles from being monitored and tracked, we use the negotiated short‐time key to encrypt the anonymous identity in the vehicle certificates. In addition, our scheme uses a new tracking method for malicious vehicles. Then, we prove the scheme through BAN logic, and it has the properties of authentication, anonymity, unlinkability, privacy protection, and traceability. Finally, we compare the computation cost and communication cost with other schemes, and the scheme has been greatly improved.     

Secure and efficient anonymous proxy signature scheme in the random oracle model

Anonymous proxy signature scheme can provide the privacy protection for the proxy signer. Recently, Yu et al. proposed an anonymous proxy signature, which can be viewed as the organic combination of proxy signature and ring signature. However, the efficiency is low. In this paper, we propose an efficient and secure proxy signature with the properties of anonymity and traceability, and it is provably secure in the random oracle model. Compared with Yu et al.＇s scheme, the scheme has higher efficiency.     

一个无条件匿名的签密算法

匿名技术在隐私保护中具有广泛应用,而签密可以在一个逻辑步骤内同时完成数字签名和公钥 加密两项功能,其代价显著低于常规“先签名再加密”方法的代价.目前的签密算法中,签密人的具体身份是公开的.该文基于Diffie-Hellman密钥交换协议和匿名签名的思想,在不可分模型下提出了一个无法追踪签密人身份的无条件匿名签密算法,并证明了该算法的正确性和安全性.     

普适环境中基于一次性公钥的匿名认证方案

提出一种基于身份的一次性公钥及签名算法,与现有算法相比,该算法具有较小的计算和通信开销。基于该算法设计了一种普适环境中的匿名认证方案,当用户进行恶意操作时,服务提供者通过和可信中心合作可以揭示恶意用户身份。方案在提供强匿名性的同时,可有效防止用户进行恶意活动。     

Ring proxy signatures

Proxy signatures have been used to enable the transfer of digital signing power within some context and ring signatures can be used to provide the anonymity of a signer. By combining the functionalities of proxy signatures and ring signatures, this paper introduces a new concept, named ring proxy signature, which is a proxy signature generated by an anonymous member from a set of potential signers. The paper also constructs the first concrete ring proxy signature scheme based on the provably secure Schnorr＇s signatures and two ID-based ring proxy signature schemes. The security analysis is provided as well.     

An efficient anonymous communication protocol for wireless sensor networks

Anonymous communication is very important for many wireless sensor networks, because it can be used to hide the identity of important nodes, such as the base station and a source node. In sensor networks, anonymous communication includes several important aspects, such as source anonymity, communication relationship anonymity, and base station anonymity. Existing sensor network anonymous schemes either cannot achieve all the anonymities or have large computation, storage, and communication overheads. In this paper, we propose an efficient anonymous communication protocol for sensor networks that can achieve all the anonymities while having small overheads on computation, storage, and communication. We compare our anonymous communication protocol with several existing schemes, and the results show that our protocol provides strong anonymity protection and has low overheads. Copyright © 2011 John Wiley & Sons, Ltd.     

基于代理签名的移动通信网络匿名漫游认证协议

随着无线移动终端的广泛应用,漫游认证、身份保密等问题显得日益突出。该文分析了现有的各种漫游认证协议在匿名性及安全性上存在的问题,指出现有协议都无法同时满足移动终端的完全匿名与访问网络对非法认证请求的过滤,进而针对性地提出了一种新的匿名认证协议。该协议基于椭圆曲线加密和代理签名机制,通过让部分移动终端随机共享代理签名密钥对的方式,实现了完全匿名和非法认证请求过滤。此外,协议运用反向密钥链实现了快速重认证。通过分析比较以及形式化验证工具AVISPA验证表明,新协议实现了完全匿名,对非法认证请求的过滤,双向认证和会话密钥的安全分发,提高了安全性,降低了计算负载,适用于能源受限的移动终端。