对一个强安全的认证密钥交换协议的分析

在2012年第15届国际公钥密码学(PKC)年会上,Fujioka等人利用密钥封装机制(KEM)提出了认证密钥交换(AKE)协议的一个通用构造,称为GC协议,并在CK+模型下证明了该协议的安全性。该文对GC协议进行了安全性分析,指出该协议是不安全的,难于抵抗不知道任何秘密信息的外部攻击者实施的假冒攻击,进一步分析了原协议安全性证明中被疏忽之处。     

Cryptanalysis of a Key Exchange Protocol Based on Commuting Matrices

A key exchange protocol is considered unsafe.The scheme is based on a set of n commuting square singular matrices of dimension n × n over a finite field,and its security is claimed to rely on the hardness of the matrix version discrete logarithm problem.However,the proposal's design allows for a clean attack strategy.We show that the key exchange protocol is vulnerable to a linear algebra attack which only requires polynomial time to obtain the equivalent keys for all given public keys.We conduct a detailed analysis on the attack method and provide some improved suggestions on the key exchange protocol based on commuting matrices.     

基于量子不经意密钥传输的量子匿名认证密钥交换协议

鉴于量子密码在密钥分配方面取得的巨大成功,人们也在尝试利用量子性质来设计其他各类密码协议。匿名认证密钥交换就是一类尚缺乏实用化量子实现途径的密码任务。为此,该文提出一个基于量子不经意密钥传输的量子匿名认证密钥交换协议。它在满足用户匿名性和实现用户与服务器双向认证的前提下,为双方建立了一个安全的会话密钥。该协议的安全性基于量子力学原理,可以对抗量子计算的攻击。此外,该协议中服务器的攻击行为要么无法奏效,要么能够与外部窃听区分开(从而被认定为欺骗),因此服务器通常不敢冒着名誉受损的风险来实施欺骗。     

Cryptanalysis and Improvement of an Anonymous Authentication Protocol for Wireless Access Networks

Authentication protocols with anonymity attracted wide attention since they could protect users’ privacy in wireless communications. Recently, Hsieh and Leu proposed an anonymous authentication protocol based on elliptic curve Diffie–Hellman problem for wireless access networks and claimed their protocol could provide anonymity. However, by proposing a concrete attack, we point out that their protocol cannot provide user anonymity. To overcome its weakness, we propose an improved protocol. We also provide an analysis of our proposed protocol to prove its superiority, even though its computational cost is slightly higher.     

基于RSA的网关口令认证密钥交换协议的分析与改进

设计安全高效的基于RSA的口令认证密钥交换协议是密码学领域的公开难题．2011年Wei等学者首次提出了一个基于RSA的可证明安全的网关口令认证密钥交换协议,并声称在随机预言模型下基于大整数的素因子分解困难性证明了协议的安全性．利用该协议中服务器端提供的预言机服务,提出一种分离攻击,攻击者只需发起几十次假冒会话便可恢复出用户的口令．攻击结果表明,该协议无法实现所声称的口令保护这一基本安全目标,突出显示了分离攻击是针对基于RSA的口令认证密钥交换协议的一种严重安全威胁．进一步指出了协议形式化安全证明中的失误,给出一个改进方案．分析结果表明,改进方案在提高安全性的同时保持了较高效率,更适于移动通信环境．     

Cryptanalysis of an Authenticated Key Agreement Protocol for Wireless Mobile Communications

With the rapid progress of wireless mobile communications, the authenticated key agreement (AKA) protocol has attracted an increasing amount of attention. However, due to the limitations of bandwidth and storage of the mobile devices, most of the existing AKA protocols are not suitable for wireless mobile communications. Recently, Lo and others presented an efficient AKA protocol based on elliptic curve cryptography and included their protocol in 3GPP2 specifications. However, in this letter, we point out that Lo and others’ protocol is vulnerable to an offline password guessing attack. To resist the attack, we also propose an efficient countermeasure.     

一种支持悬赏的匿名电子举报方案的安全性分析及设计

 对Miao-Wang-Miao-Xiong匿名电子举报方案进行了安全性分析,指出其存在的安全性缺陷,该方案不满足其要求的举报信息机密性,以及不满足对举报人提供有效的激励机制.设计了破坏这两种性质的攻击方法.为设计满足要求的支持悬赏的匿名电子举报方案,利用安全的基于双线性对的举报受理者公钥加密方案、安全的指定验证者的环签名方案提出了一种支持悬赏的匿名电子举报方案设计模式.经安全性分析,设计模式是安全的.     

通用可组合的组密钥交换协议

该文提出了一个通用可组合框架下的组密钥交换理想函数,并在防篡改硬件令牌的基础上,利用部分隔离状态下证据不可区分知识证明,设计了一个组密钥交换协议,安全地实现了这个理想函数。和采用CRS模型的协议相比,降低了把整个信任集中于一处带来的风险。提出的组密钥交换协议经过证明具有AKE安全,并且能够抵抗适应性敌手攻击和恶意参与者攻击。     

基于CPK的可证安全组群密钥交换协议

CPK组合公钥密码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。丈中基于CPK设计了一个高效常数轮的组群密钥交挟协议,并且协议在CDH假设下可证安全和具有完美的前向安全性。该协议只需两轮通信即可协商一个组群会话密钥,无论在通信以及计算方面均很高效。此外该协议提供了一个设计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。     

Internet密钥交换协议的分析和实施

Internet密钥交换协议是IPSec协议体系中的重要组成部分,它为IPSec提供了协商安全参数的机制。本文首先分析了IKE在IPSec安全协议体系中的位置及作用,之后详细介绍了它实现协商的机制,并对IKE的实施提出了一种解决方案,最后对IKE的应用前景进行了一定的探讨。     

IKE协议的安全性分析

在简略介绍IKE协议RFC2409工作机制的基础上,对协议现有的安全问题进行了分析,并针对协议阶段1中主模式与积极模式下身份保护存在的问题提出了协议修改建议,对阶段1中安全联盟建立的可靠性进行了探讨以加强协议抵御DoS攻击的能力。     

基于口令的鉴别密钥交换协议设计

网络用户的身份鉴别和密钥交换问题是网络安全的核心问题,目前最常见的鉴别密钥交换协议为基于口令的鉴别密钥交换(PAKE)协议。论文讨论了PAKE协议的设计目的、基本模式及其安全需求,并给出了双方模式和三方模式PAKE协议的交互过程,为网络安全协议的设计提供了参考。     

认证的密钥交换协议及SVO逻辑证明

在环境受限的无线通信网络环境中,身份认证和会话密钥的协商是确保通信双方能否建立安全会话的关键。为使认证和密钥建立协议中采用的密码技术能适合受限通信环境中的应用,提出一个基于身份的认证的密钥建立协议,并使用SVO逻辑证明设计协议的安全目标。     

环Zn上椭圆曲线的密钥交换协议

设n=pq,p,q为奇素数,环Z_n上的椭圆曲线E_n(a,b)的SOM密钥交换协议与QV密钥交换协议均选取E_n(a,b)上的阶为M_n=lcm{#E_p(a,b),＃E_q(a,b)}的点G作为公钥(称G为基点),并且限定其对应的E_p(a,b)和E_q(a,b)均为循环群,这就限制了这两个协议只能选择一类特殊的椭圆曲线E_n(a,b)构作密钥交换协议.本文指出,E_p(a,b)和Eq(a,b)均为循环群这一限定是不必要的.本文给出了E_n(a,b)上存在阶为M_n的点G的一个充分必要条件,并给出一个例子,其中E_p(a,b)为循环群,E_q(a,b)为非循环群,且对应的E_n(a,b)上有阶为M_n的点G.同时,本文选取E_n(a,b)上阶为lcm{n₁,m₁}的点作为基点,这里n₁,m₁分别为E_p(a,b)和E_q(a,b)的最大循环子群的阶.这样,就能够选择更多的椭圆曲线E_n(a,b),用来构作密钥交换协议(包括将两方之间的密钥交换协议扩展到三方).     

通用可组合的三方口令认证密钥交换协议

现有的许多三方口令认证密钥交换(3PAKE)协议都被发现是不安全的。该文基于通用可组合(UC)模型,定义了3PAKE理想函数。在两方口令认证密钥交换理想函数辅助的混合模型下,构造了一个实现3PAKE理想函数的3PAKE协议。新的协议由中间密钥生成、消息认证传输和会话密钥生成3个阶段构成。该协议是UC安全的,并且结构简单。     

适用于移动应用的口令认证多密钥协商协议

To achieve privacy and authentication simultaneously in mobile applications, various Three-party Password-authenticated key exchange (3PAKE) protocols have been proposed. However, some of these protocols are vulnerable to conventional attacks or have low efficiency so that they cannot be applied to mobile applications . In this paper, we proposed a password-authenticated multiple key exchange protocol for mobile applications using elliptic curve cryptosystem. The proposed protocol can achieve efficiency, reliability, flexibility and scalability at the same time. Compared with related works, the proposed protocol is more suitable and practical for mobile applications .     

基于通用可组合三方密码的密匙交换协议

Within the framework of universal composability, an appropriate ideal functionality that captures the basic security requirements of three party password-based key exchange was defined. An efficient real-word three party password-based key exchange protocol was also proposed. This protocol securely realizes the ideal functionality with respect to static party corruption. Thus it provides security guarantees under arbitrary composition with other protocols.     

通用可组合符号化分析群组密钥协商协议

Canetti and Herzog have already proposed universally composable symbolic analysis (UCSA) to analyze mutual authentication and key exchange protocols. However, they do not analyze group key exchange protocol. Therefore, this paper explores an approach to analyze group key exchange protocols, which realize automation and guarantee the soundness of cryptography. Considered that there exist many kinds of group key exchange protocols and the participants’ number of each protocol is arbitrary. So this paper takes the case of Burmester-Desmedt (BD) protocol with three participants against passive adversary (3-BD-Passive). In a nutshell, our works lay the root for analyzing group key exchange protocols automatically without sacrificing soundness of cryptography.     

标准模型下高效的基于口令认证密钥协商协议

基于口令的认证密钥协商协议是利用预先共享的口令协商安全性较高的密钥。现有的基于口令认证密钥协商协议大多需要较大的计算量,或者只在随机预言模型下证明了协议的安全性。该文提出了新的标准模型下基于口令密钥协商协议,协议只需要一个生成元。 与其它标准模型下的协议相比,新协议不需要CPA或CCA2安全的加密方案,因而具有计算复杂度低和协议描述简单的特点。相对于殷胤等人在标准模型下可证安全的加密密钥协商协议一文中提出的协议,新协议将指数运算降低了64%。最后,基于DDH假设,在标准模型下证明了协议的安全性。