基于RSA的网关口令认证密钥交换协议

网关口令认证密钥交换协议是一个三方协议,使得用户和网关在服务器的协助下建立起一个安全的会话密钥,从而实现用户和网关之间的安全通信.已有的网关口令认证密钥交换协议都是基于Diffie-Hellman密钥交换设计的.利用张木想所设计的PEKEP协议,提出了基于RSA体制的可证明安全的网关口令认证密钥交换协议.在随机预言模型...     

改进的三方口令认证密钥交换协议

基于三方的口令认证密钥交换（3PAKE）协议是客户通过与可信服务器共享一个口令验证元,在两客户进行通信时通过此可信服务器进行会话密钥的建立与共享,从而进行通信。首先对李文敏等人提出的协议进行安全性分析,发现该协议易受离线字典攻击和服务器泄露攻击。提出了一个改进协议,该协议能够提供双向认证、会话密钥机密性和前向安全性,能够有效抵抗多种攻击,包括离线字典攻击和服务器泄露攻击。     

具有强安全性的三方口令认证密钥交换协议

大部分口令认证密钥交换(PAKE)协议的设计者忽略了长期密钥泄露可能造成的危害.文中发现仅仅依靠口令的安全性设计可以抵抗口令泄露攻击的三方PAKE协议是不可能的,所以文中采取服务器通过公钥实现认证的方法,设计一个可以抵抗口令泄露攻击的强安全性协议,其在随机预示和理想密码模型下基于ECGDH假设具有前向安全的特性.     

一个前向安全的基于口令认证的三方密钥交换协议

目前,文献中提出的基于口令认证的密钥交换协议,很多都是针对两方的情形设计的,即通信双方为客户与服务器,它们通过一个预先共享的口令来进行认证的密钥交换.随着现代通信环境的快速变化,需要能为任意客户间构建一个端到端的安全信道,这种应用的情形与那些文献中所考虑的有很大区别.针对这种情形,文中提出了一个可证前向安全的基于口令认证的三方密钥交换协议,使通信双方在认证服务器的帮助下能相互进行认证并建立一个会话密钥.与前人提出的基于口令认证的三方密钥交换协议相比,该协议在计算代价和通信代价上都较有效,因而更适用于资源受限的环境.此协议的安全性是在口令型的选择基Gap Diffie-Hellman问题难解的假设前提下在随机谕示模型下证明的.     

基于验证元的三方密钥交换协议的分析和改进

对现有的一个典型的基于验证元的三方密钥交换协议——ZZJ协议进行分析,指出它的不安全性。在此基础上针对现有的大多数基于验证元的3PAKE协议均难以抵御服务器密钥泄露攻击的现状,提出一个新的基于验证元的三方密钥交换协议——NZZJ协议。通过安全性分析,证明该协议能够抵御服务器密钥泄露攻击、未知密钥共享和内部人攻击等常见的安全威胁。     

简单的三方口令密钥交换协议

基于口令认证的三方密钥交换协议（3PAKE）是通信双方在认证服务器的帮助下能在公开非安全的信道上协商并建立一个共享会话密钥。虽然目前有不少该方面的研究,但多数后来被证实易受攻击。本文给合以往的研究,提出一个不需服务器公钥体系的简单的基于口令认证的三方密钥交换协议。本文的协议不仅能抵抗各种攻击,而且计算成本和通信成本都比较低。     

标准模型下高效的三方口令认证密钥交换协议

三方口令认证密钥交换协议允许两个分别与服务器共享不同口令的用户在服务器的协助下建立共享的会话密钥,从而实现了用户间端到端的安全通信.现阶段,多数的三方口令认证密钥交换协议都是在随机预言模型下可证明安全的.但在实际应用中,利用哈希函数对随机预言函数进行实例化的时候会给随机预言模型下可证明安全的协议带来安全隐患,甚至将导致协议不安全.以基于ElGamal加密的平滑投射哈希函数为工具,在共同参考串模型下设计了一种高效的三方口令认证密钥交换协议,并且在标准模型下基于DDH假设证明了协议的安全性.与已有的同类协议相比,该协议在同等的安全假设下具有更高的计算效率和通信效率,因此更适用于大规模的端到端通信环境.     

基于椭圆曲线的加密密钥交换协议

加密密钥交换协议(EKE)的目的是利用安全性低的口令协商安全性高的密钥,进而利用密钥对以后的通信进行加密或身份认证,从而实现安全通信.基于验证元的EKE是针对服务器泄露攻击问题提出的.本文基于椭圆曲线密码系统的特点,给出了一个基于验证元的3EKE,该协议中,服务器通过口令实现对用户的认证;协议能够抵抗服务器泄露等攻击,...     

适用于双方频繁通信的密钥交换协议

首先对以前提出的一个高效的基于验证元的三方密钥交换协议进行了安全性分析,指出了它容易受到服务器密钥泄露攻击等安全威胁,且缺乏前向安全性;并以此为基础,针对大多数现存的基于验证元的3PAKE协议均难以抵御服务器密钥泄露攻击的现状,提出了一个新的3PAKE协议。通过安全性分析,证明了新协议比原协议更安全,能够抵御各种已知的攻击,且与现有的大多数同类协议相比具有更高的效率。     

具有强匿名性的网关口令认证密钥交换协议

网关口令认证密钥交换协议允许用户和网关在服务器的协助下建立起一个共享的会话密钥,其中用户和服务器之间的认证通过低熵的口令来完成.已有的网关口令认证密钥交换协议对用户的匿名性研究不足.该文基于Diffie-Hellman密钥交换提出了具有强匿名性的网关口令认证密钥交换协议,并且在随机预言模型下基于标准的DDH假设证明了协议的安全性.新协议可以抵抗不可检测在线字典攻击并且计算效率高,安全性和计算效率都优于已有的同类协议.     

Efficient verifier-based password-authenticated key exchange in the three-party setting

In the last few years, researchers have extensively studied the password-authenticated key exchange (PAKE) in the three-party setting. The fundamental security goal of PAKE is security against dictionary attacks. The protocols for verifier-based PAKE are additionally required to be secure against server compromise. Some verifier-based PAKE schemes in the three-party setting have been suggested to solve the server compromise problem. Unfortunately, the protocols are vulnerable to an off-line dictionary attack. In this paper, we present an efficient verifier-based PAKE protocol for three-parties that is secure against known-key attacks and provides forward secrecy. To the best of our knowledge, the proposed protocol is the first secure three-party verifier-based PAKE protocol in the literature.     

A communication-efficient three-party password authenticated key exchange protocol

Three-party password authenticated key exchange (3PAKE) protocols allow two users (clients) to establish a session key through an authentication server over an insecure channel. Clients only share an easy-to-remember password with the trusted server. In the related literature, most schemes employ the server public keys to ensure the identities of both the servers and symmetric cryptosystems to encrypt the messages. This paper describes an efficient 3PAKE based on LHL-3PAKE proposed by Lee et al. Our 3PAKE requires neither the server public keys nor symmetric cryptosystems such as DES. The formal proof of security of our 3PAKE is based on the computational Diffie-Hellman assumption in the random oracle model along with a parallel version of the proposed 3PAKE. The comparisons have shown that our 3PAKE is more practical than other 3PAKEs.     

Provably secure three-party password authenticated key exchange protocol in the standard model

Three-party password authenticated key exchange protocol is a very practical mechanism to establish secure session key through authenticating each other with the help of a trusted server. Most three-party password authenticated key exchange protocols only guarantee security in the random oracle model. However, a random oracle based cryptographic construction may be insecure when the oracle is replaced by real function. Moreover, some previous unknown attacks appear with the advance of the adversary capability. Therefore, a suitable standard model which can imitate a wider variety of attack scenarios for 3PAKE protocol is needed. Aim at resisting dictionary attack, unknown key-share attack and password-compromise impersonation attack, an expanded standard model for 3PAKE protocol is given. Meanwhile, through applying ElGamal encryption scheme and pseudorandom function, a specific three-party password authenticated key exchange protocol is proposed. The security of the proposed protocol is proven in the new standard model. The result shows that the present protocol has stronger security by comparing with other existing protocols, which covers the following security properties: (1) semantic security, (2) key privacy, (3) client-to-server authentication, (4) mutual authentication, (5) resistance to various known attacks, and (6) forward security.     

An efficient client–client password-based authentication scheme with provable security

Recently, Tso proposed a three-party password-based authenticated key exchange (3PAKE) protocol. This protocol allows two clients to authenticate each other and establish a secure session key through a server over an insecure channel. The main security goals of such protocols are authentication and privacy. However, we show that Tso’s protocol achieves neither authentication goal nor privacy goal. In this paper, we indicate that the privacy and authentication goals of Tso’s protocol will be broken by off-line password guessing attack and impersonation attack, respectively. To overcome the weaknesses, we propose an improved 3PAKE protocol to achieve more security and performance than related protocols. The security of the proposed improved protocol is proved in random oracle model.     

An novel three-party authenticated key exchange protocol using one-time key

Three-party authenticated key exchange protocol (3PAKE) is an important cryptographic technique for secure communication which allows two parties to agree a new secure session key with the help of a trusted server. In this paper, we propose a new three-party authenticated key exchange protocol which aims to achieve more efficiency with the same security level of other existing 3PAKE protocols. Security analysis and formal verification using AVISPA tools show that the proposed protocol is secure against various known attacks. Comparing with other typical 3PAKE protocols, the proposed protocol is more efficient with less computation complexity.     

Security analysis and improvements of a communication-efficient three-party password authenticated key exchange protocol

Three-party password-authenticated key exchange (3PAKE) protocols allow two clients to establish secure communication channels over a public network merely by sharing a human-memorable (low-entropy) password with a trusted server. In this paper, we first show that the 3PAKE protocol introduced by Chang, Hwang, and Yang is insecure against even passive attackers. Thereafter, we propose two kinds of improvement that can remedy the security flaw in their protocol. Finally, we present simulations to measure the execution time to show the efficiency of our two improvements.