基于移动端协助的硬口令认证密钥交换协议

针对现有口令认证密钥交换协议易受各种网络攻击,影响用户私密信息安全的问题,提出一种基于移动端协助的硬口令认证密钥交换协议,在移动端的辅助下,允许用户使用单一口令建立与服务器之间的安全会话。协议中,用户无须记忆任何复杂的私钥信息,即使移动设备丢失、被盗或遭受恶意软件侵袭,也不会损害用户信息。安全性和性能分析表明,协议明显降低了服务器的计算消耗,大大提高了用户私密信息的安全性,可以抵御字典攻击、中间人攻击等的影响,减轻用户记忆负担,缓解存储压力,易于部署。     

基于身份的可认证非对称群组密钥协商协议

非对称群组密钥协商协议(asymmetric group key agreement, AGKA)能使群组内部成员安全地传递信息.随着大规模分布式网络协同计算的发展,参加安全协同计算的成员可能来自于不同领域、不同时区、不同云端及不同类型的网络.现有的AGKA不能满足来自于跨域及异构网络之间群组成员的安全信息交换,且安全性仅局限于抗被动攻击.提出一种基于身份的可认证非对称群组密钥协商协议(identity-based authenticated asymmetric group key agreement, IB-AAGKA),该协议实现一轮非对称群组密钥协商,解决群组成员因时区差异而不能保持多轮在线密钥协商的问题;可实现匿名性与可认证性;支持节点的动态群组密钥更新,实现了群组密钥向前保密与向后保密安全性.在decisional bilinear Diffie-Hellman(DBDH)困难假设下,证明了协议的安全性,并分析了协议的性能.     

基于口令的群密钥协商协议

基于口令的群密钥协商协议的目的是利用低熵的口令协商出高熵的会话密钥,并利用该会话密钥进行安全的通信,达到成员之间多方安全的要求。引入2个随机数来提高安全性,使用Hash函数对口令进行优化确保口令的新鲜性,提出一个标准模型下的可证安全的基于口令的协议,并对其进行安全性分析。     

一种可认证的群组密钥协商协议

群组密钥协商协议可以使得所有组员协商出一个相同的密钥,该密钥可以被用到后续的组员之间的安全通信中,保证群组通信的机密性、完整性和真实性。本文在可认证双方密钥认证协议和BD群组密钥协商协议的基础上,提出了一种可认证的群组密钥协商协议(ABD)。和BD相比,ABD不仅能抵抗被动攻击还能抵抗主动攻击。     

基于扩展混沌映射的远程医疗信息系统认证方案

针对远程医疗信息系统（TMIS）的实时应用场景,提出了一种安全高效的基于扩展混沌映射的切比雪夫多服务器认证协议。该方案使用随机数和注册中心的私钥为用户/应用服务器的身份加密,有效地支持用户和应用服务器的撤销和重新注册。同时,还利用“模糊验证因子”技术避免离线密码猜测攻击,利用“honeywords”技术有效避免在线密码猜测攻击。该方案在公共信道上传输的与用户身份相关的信息均使用随机数或随机数的计算结果进行加密,因此可以为用户提供强匿名性。通过BAN逻辑证明该协议可以实现用户和服务器的安全相互认证;同时,使用非正式安全证明该协议可以抵抗多种已知攻击。     

标准模型下基于口令的群密钥协商协议

基于口令的群密钥协商协议的目的是利用低熵的口令协商出高熵的会话密钥,并应用此会话密钥进行安全的通信,达到成员之间多方安全的要求。在Burmester及Desmedt协议的基础上,引入伪随机函数集和签名方案,提出一个标准模型下的可证安全的基于口令的协议,并对其进行安全性分析。     

基于口令的远程身份认证及密钥协商协议

基于口令的身份认证协议是研究的热点。分析了一个低开销的基于随机数的远程身份认证协议的安全性,指出了该协议的安全缺陷。构造了一个基于随机数和Hash函数、使用智能卡的远程身份认证和密钥协商协议：PUAKP协议。该协议使用随机数,避免了使用时戳带来的重放攻击的潜在风险。该协议允许用户自主选择和更改口令,实现了双向认证,有较小的计算开销;能够抵御中间人攻击;具有口令错误敏感性、口令的主机非透明性和强安全修复性;生成的会话密钥具有新鲜性、机密性、已知密钥安全性和前向安全性。     

运用DH-EKE增强WTLS握手协议的安全性

WTLS握手协议不满足前向安全性,非匿名验证模式下不满足用户匿名性,完全匿名模式下易遭受中间人攻击.DH-EKE协议具有认证的密钥协商功能,将改进的DH-EKE集成到WTLS握手协议中,只需使用可记忆的用户口令,不需使用鉴权证书及数字签名.该方案适用于完全匿名的验证模式,可抵御中间人攻击和字典式攻击,且在服务器中不直接存储口令,攻击者即使攻破服务器获得口令文件也无法冒充用户,能够在WTLS握手协议中实现简单身份认证和安全密钥交换.     

A secure dynamic ID based remote user authentication scheme for multi-server environment

Since the number of server providing the facilities for the user is usually more than one, the authentication protocols for multi-server environment are required for practical applications. Most of password authentication schemes for multi-server environment are based on static ID, so the adversary can use this information to trace and identify the user's requests. It is unfavorable to be applied to special applications, such as e-commerce. In this paper, we develop a secure dynamic ID based remote user authentication scheme to achieve user's anonymity. The proposed scheme only uses hashing functions to implement a robust authentication scheme for the multi-server environment. It provides a secure method to update password without the help of third trusted party. The proposed scheme does not only satisfy all requirements for multi-server environment but also achieve efficient computation. Besides, our scheme provides complete functionality to suit with the real applications.     

有效的强安全组群密钥交换协议

组合公钥密码(CPK)体制无需证书来保证公钥的真实性,克服了用户私钥完全由密钥管理中心生成的问题。基于CPK设计了一个常数轮的组群密钥交换协议,该协议在CDH假设下可证安全并具有完美的前向安全性,只需两轮通信即可协商一个组群会话密钥,在通信和计算方面都很高效;并且高效地支持组群成员动态加入/离开,尤其对于多成员加入/离开的情况,只需额外的少量通信和计算即可更新组群密钥,确保了前向保密性和后向保密性。此外,本协议提供了强安全性保证,它能保持密钥的秘密性,除非某一方的临时私钥和长期私钥同时被泄露。最后,该协议提供了一个设计常数轮强安全组群密钥交换协议的方法,大部分的秘密共享体制均可直接应用于该协议。     

基于组合公钥的用户公钥认证算法

为解决组合公钥算法中的共谋攻击问题及用户私钥托管问题,提出一种基于组合公钥的用户公钥认证算法。其中,密钥管理中心生成用户的签名公私钥矩阵,用户随机生成自己的公私钥对,密钥管理中心使用用户的签名私钥对用户的公钥进行签名。理论分析证明,该算法使用签名私钥矩阵代替单个的签名私钥,从而扩大了签名私钥的空间,增强了系统的安全性。     

基于混沌映射的用户匿名三方口令认证密钥协商协议

在基于混沌的三方口令认证密钥协商协议中,用户通过低熵的口令实现相互认证和共享会话密钥,以避免在身份认证过程中公钥基础设施或存储用户长期密钥的安全威胁。通过分析Lee提出的基于混沌映射的口令认证密钥协商协议,发现其协议不能进行口令变更,而且仅适用于用户和服务器之间的两方通信。为了改进此方案,提出两个基于切比雪夫混沌映射的用户匿名三方口令认证密钥协商协议,包括基于时钟同步的密钥协商方案和基于随机数的密钥协商方案。其中基于时钟同步的用户匿名三方口令认证密钥协商协议通信量少,基于随机数的用户匿名三方口令认证密钥协商协议更容易实现。两个方案的优点是用户仅选择一个简单的口令进行相互认证和密钥协商,服务器不需要再保护用户口令表,避免了口令相关的攻击,而且在相互认证过程中用户使用临时身份和哈希函数,实现用户匿名性,在增强协议安全性的同时,减少了通信过程中消息的数量,提高了协议的执行效率,具有完美前向安全,并用BAN逻辑证明了其安全性。     

A strong user authentication scheme with smart cards for wireless communications

Seamless roaming over wireless network is highly desirable to mobile users, and security such as authentication of mobile users is challenging. Recently, due to tamper-resistance and convenience in managing a password file, some smart card based secure authentication schemes have been proposed. This paper shows some security weaknesses in those schemes. As the main contribution of this paper, a secure and light-weight authentication scheme with user anonymity is presented. It is simple to implement for mobile user since it only performs a symmetric encryption/decryption operation. Having this feature, it is more suitable for the low-power and resource-limited mobile devices. In addition, it requires four message exchanges between mobile user, foreign agent and home agent. Thus, this protocol enjoys both computation and communication efficiency as compared to the well-known authentication schemes. As a special case, we consider the authentication protocol when a user is located in his/her home network. Also, the session key will be used only once between the mobile user and the visited network. Besides, security analysis demonstrates that our scheme enjoys important security attributes such as preventing the various kinds of attacks, single registration, user anonymity, no password/verifier table, and high efficiency in password authentication, etc. Moreover, one of the new features in our proposal is: it is secure in the case that the information stored in the smart card is disclosed but the user password of the smart card owner is unknown to the attacker. To the best of our knowledge, until now no user authentication scheme for wireless communications has been proposed to prevent from smart card breach. Finally, performance analysis shows that compared with known smart card based authentication protocols, our proposed scheme is more simple, secure and efficient.     

WSN中基于ECC的轻量级认证密钥协商协议

为解决无线传感器网络密钥管理与认证协议设计中由于节点频繁移动所带来的计算量、存储量等资源消耗过大问题,提出了一种基于ECC的轻量级认证密钥协商协议。该协议主要用于网络中任意用户节点之间,以及用户节点与网络之间的双向认证和会话密钥的协商。方案采用ECC进行会话密钥协商,结合AES对称密钥加密技术保证信息传输过程的保密性。与传统的密钥协商协议相比,能够在更小的密钥量下提供更大的安全性,并减少了对节点计算量和存储量的需求。该协议在ID-BJM安全模型下证明了其安全性。分析结果表明,该协议满足前后向安全性和PKG前向安全性。     

Access control protocols with two-layer architecture for wireless networks

In this paper we study two access control protocols which have similar two-layer access control architectures for wireless networks in public places. The first protocol, called the Lancaster protocol, employs user password for authentication and enforces access control at the IP layer; while the second protocol, referred to as the Stanford protocol, uses public key cryptosystems (PKC) for authentication and performs access control at the link layer. Although both protocols are intended to restrict access to wireless networks only to authorized users, our analysis shows that both protocols have serious security flaws which make them vulnerable to attacks. Then we propose a password-based protocol and a PKC-based protocol for the Lancaster architecture and the Stanford architecture, respectively. Both of our protocols provide mutual authentication, perfect forward secrecy and access control for wireless networks. Moreover, they also provide DoS resistance and identity confidentiality for the client. We present detailed security and performance analysis for our protocols, and show that both of our protocols are secure and efficient for access control in wireless networks.     

A group key agreement protocol for intelligent internet of things system

The application of intelligent computing in Internet of Things (IoTs) makes IoTs systems such as telemedicine, in-vehicle IoT, and smart home more intelligent and efficient. Secure communication and secure resource sharing among intelligent terminals are essential. A secure communication channel for intelligent terminals can be established through group key agreement (GKA), thereby ensuring the security communication and resource sharing for intelligent terminals. Taking into account the confidentiality level of the shared resources of each terminal, and the different permissions of the resource sharing of each terminal, a GKA protocol for intelligent IoTs is proposed. Compared with previous work, this protocol mainly has the following advantages: (1) The hidden attribute identity authentication technology can achieve the security of identity authentication and protect personal privacy from being leaked; (2) Only intelligent terminals satisfying the threshold required of the GKA can participate in the GKA, which increases the security of group communication; (3) Low-level group terminals can obtain new permissions to participate in high-level group communication if they meet certain conditions. High-level group terminals can participate in low-level group communication through permission authentication, which increases the flexibility and security of group communication; (4) The intelligent terminals in the group can use their own attribute permission parameters to calculate the group key. They can verify the correctness of the calculated group key through a functional relationship, and does not need to exchange information with other members in the same group. Under the hardness assumption of inverse computational Diffie-Hellman problem and discrete logarithm problem, it is proven that the protocol has high security, and compared with the cited literatures, it has good advantages in terms of computational complexity, time cost and communication energy cost.     

基于云模型理论的群体用户画像模型

为了能够对群体用户中不确定性和模糊性的行为精确的定量分析和定性相似度的计算,设计了一个基于云模型理论的定性相似度算法来给群体用户构建画像模型.首先,采用识别客户价值最广泛的RFM （Recency,Frequency,Monetary）模型来细分用户.其次,通过云模型变换算法将用户的行为转换为用户的云模型标签,该云模型标签就是对用户行为的一次定量表示,然后通过云模型聚类算法来划分出不同的客户类型,作为客户画像的模型,利用该模型指导商业营销活动.     

An enhanced smart card based remote user password authentication scheme

Smart card based password authentication is one of the simplest and efficient authentication mechanisms to ensure secure communication in insecure network environments. Recently, Chen et al. have pointed out the weaknesses of some password authentication schemes and proposed a robust smart card based remote user password authentication scheme to improve the security. As per their claims, their scheme is efficient and can ensure forward secrecy of the session key. However, we find that Chen et al.'s scheme cannot really ensure forward secrecy, and it cannot detect the wrong password in login phase. Besides, the password change phase of Chen et al.'s scheme is unfriendly and inefficient since the user has to communicate with the server to update his/her password. In this paper, we propose a modified smart card based remote user password authentication scheme to overcome the aforementioned weaknesses. The analysis shows that our proposed scheme is user friendly and more secure than other related schemes.     

A lightweight authentication and key agreement protocol preserving user anonymity

Nowadays with widespread employment of the Internet, servers provide various services for legal users. The vital issue in client/server connections is authentication protocols that make the communication channel safe and secure against famous attacks. Recently, Kumari et al. and Chaudhry et al. proposed two authentication and key agreement protocols and illustrated that their proposed protocols are secure against various security attacks. However, in this paper we demonstrate that both protocols are vulnerable to off-line password guessing attacks. Moreover, we show that Kumari et al.’s protocol does not provide the property of user anonymity. In order to overcome these weaknesses, we propose a lightweight authentication and key agreement protocol. The correctness of the proposed protocol is proved using BAN logic. Security analysis demonstrates that the proposed protocol resists various security attacks and provides user anonymity. Furthermore, performance analysis confirms that the computation cost of the proposed protocol is acceptable.

     

对三个多服务器环境下匿名认证协议的分析

设计安全高效的多服务器环境下匿名身份认证协议是当前安全协议领域的研究热点。基于广泛接受的攻击者模型,对多服务器环境下的三个代表性匿名认证协议进行了安全性分析.指出Wan等协议无法实现所声称的离线口令猜测攻击,且未实现用户匿名性和前向安全性;指出Amin等协议同样不能抵抗离线口令猜测攻击,且不能提供匿名性,对两种破坏前向安全性的攻击是脆弱的;指出Reedy等协议不能抵抗所声称的用户仿冒攻击和离线口令猜测攻击,且无法实现用户不可追踪性.突出强调这些协议失败的根本原因在于,违反协议设计的三个基本原则：公钥原则、用户匿名性原则和前向安全性原则.明确协议的具体失误之处,并提出相应修正方法.