Analysis and Improvement of Cross-Realm Client-to-Client Password Authenticated Key Exchange Protocols

Because cross-realm C2C-PAKE （client-to-client password authenticated key exchange） protocols can not resist some attacks, this paper writes up new attacks on two representative protocols, then designs a new cross-realm C2C-PAKE protocol with signature and optimal number of rounds for a client （only 2-rounds between a client and a server）. Finally, it is proved that the new protocol can be resistant to all known attacks through heuristic analysis and that it brings more security through the comparisons of security properties with other protocols.

格上无非交互式零知识证明的两轮三方PAKE协议

针对现有基于格的三方口令认证密钥交换(PAKE)协议通信轮次较多、执行效率较低等问题,提出一种格上无非交互式零知识证明的两轮三方PAKE协议。首先,利用非适应性近似平滑投影哈希函数实现密钥交换,在不使用非交互式零知识(NIZK)证明的前提下,降低协议的通信轮数;其次,利用哈希值和投影哈希值构造会话密钥,不需要使用随机预言机,避免了随机预言机导致的潜在口令猜测攻击。在标准模型下给出所提协议的形式化安全证明。仿真结果表明,与基于格的三方PAKE协议相比,所提协议的执行时间在客户端缩短了89.2%~98.6%,在服务器端缩短了19.0%~91.6%。验证了所提协议能够抵抗量子攻击,具有较高的执行效率,同时减少了协议通信轮数。

An Enhanced Dragonfly Key Exchange Protocol against Offline Dictionary Attack

Dragonfly is Password Authenticated Key Exchange protocol that uses a shared session key to authenticate parties based on pre-shared secret password. It was claimed that this protocol was secure against off-line dictionary attack, but a new research has proved its vulnerability to off-line dictionary attack and proving step was applied by using “Patched Protocol” which was based on public key validation. Unfortunately, this step caused a raise in the computation cost, which made this protocol less appealing than its competitors. We proposed an alternate enhancement to keep this protocol secure without any extra computation cost that was known as “Enhanced Dragonfly”. This solution based on two-pre-shared secret passwords instead of one and the rounds between parties had compressed into two rounds instead of four. We prove that the enhanced-Dragonfly protocol is secure against off-line dictionary attacks by analyzing its security properties using the Scyther tool. A simulation was developed to measure the execution time of the enhanced protocol, which was found to be much less than the execution time of patched Dragonfly. The off-line dictionary attack time is consumed for few days if the dictionary size is 10,000. According to this, the use of the enhanced Dragonfly is more efficient than the patched Dragonfly.

Scalable protocol for cross-domain group password-based authenticated key exchange

Cross-domain password-based authenticated key exchange （PAKE） protocols have been studied for many years. However, these protocols are mainly focusing on multi-participant within a single domain in an open network environment. This paper proposes a novel approach for designing a cross-domain group PAKE protocol, that primarily handles with the setting of multi-participant in the multi- domain. Moreover, our protocol is proved secure against active adversary in the Real-or-Random （ROR） model. In our protocol, no interaction occurs between any two domain authentication servers. They are regarded as ephemeral certificate authorities （CAs） to certify key materials that participants might subsequently use to exchange and agree on group session key. We further justify the computational complexity and measure the average computation time of our protocol. To the best of our knowledge, this is the first work to analyze and discuss a provably secure multi-participant cross-domain group PAKE protocol.

Simple Three-Party Password Authenticated Key Exchange Protocol

Three-party password authenticated key exchange (3PAKE) protocol plays a significant role in the history of secure communication area in which two clients agree a robust session key in an authentic manner based on passwords. In recent years, researchers focused on developing simple 3PAKE (S-3PAKE) protocol to gain system e?ciency while preserving security robustness for the system. In this study, we first demonstrate how an undetectable on-line dictionary attack can be successfully applied over three existing S-3PAKE schemes. An error correction code (ECC) based S-3PAKE protocol is then introduced to eliminate the identified authentication weakness.

Simple and Efficient Password-Based Authenticated Key Exchange Protocol

Password-based authenticated key exchange(PAKE) protocols are cryptographic primitives which enable two entities,who only share a memorable password,to identify each other and to communicate over a public unreliable network with a secure session key.In this paper,we propose a simple,efficient and provably secure PAKE protocol based on Diffie-Hellman key exchange and cryptographic hash function.Our protocol is secure against dictionary attacks.Its security is proved based on the hardness of the computational Diffie-Hellman problem in the random oracle model.

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。

基于ECDSA的三方口令认证密钥交换协议

提出一种基于椭圆曲线数字签名算法(ECDSA)的三方口令认证密钥交换协议。将ECDSA分为公钥生成、签名过程和验证过程3个阶段,在此基础上,设计协议过程、双向认证机制,使任意2个用户通过服务器能进行身份认证和密钥交换。分析结果表明,该协议能降低计算难度和存储开销,抵抗字典攻击和服务器泄露攻击。

基于椭圆曲线的强壮高效口令认证密钥协商方案

提出一个适合远程用户的口令认证和密钥交换协议,该协议在不信任网络中运行,无需认证表和交换密钥.新的协议可抵抗被动或主动入侵,甚至内部攻击者的字典攻击,即使弱的口令也可以安全地使用.协议还满足完备的前向安全性,在当前口令泄露后不影响以前会话的安全性.在所提协议中,用户口令并不是以明文的形式储存,因此当攻击者获取智能卡后,并不能直接登录到主机.文中协议高效且安全,可广泛应用于需要口令认证的环境.同以往工作相比,所提协议对分布式或便携式设备更加有效.

可证安全的口令认证/密钥交换协议的研究动态

口令认证/密钥交换(PAKE协议)协议允许通信双方利用短小易记的口令在不安全的网络上进行相互认证并建立安全的会话密钥,它有着非常广泛的实际应用背景和重要的理论意义。文章介绍了PAKE协议的研究发展动态、PAKE协议的通信模型和PAKE协议标准化工作的研究进展,分析了现有标准候选协议的优劣,指出了需要进一步研究的问题。

UC安全的双向口令认证密钥协商协议

针对多数口令密钥协商(PAKE)协议不具备双向认证功能的问题,基于通用可组合(UC)模型,提出一种UC安全的双向口令认证密钥协商(MPAKE)协议。定义具有双向认证功能的PAKE协议理想函数,描述实体之间的双向认证关系,并利用联合状态UC模型构造实现该理想函数的协议,使协议实体之间可以使用共享参数。该协议基于口令实现了双向认证,并能够协商出会话密钥。通过构造仿真器及其执行的操作分析MPAKE的不可区分性,从而证明该协议是UC安全的,并且结构简单,可保证在任意多方环境中并行运行时的安全。

改进的跨域基于指纹和口令认证的密钥交换协议

提出一种改进的跨域基于指纹与智能手机协助的口令认证密钥交换协议,并证明该协议具有语义安全性、密钥保密性,且能对抗不可检测在线字典攻击、离线字典攻击,实现服务器与用户之间的双向认证,安全性分析表明该协议是安全有效的。