Lu Li, Jinsong Han, Yunhao Liu, Lei Hu · 7 authors
Most of the current trust models in peer-to-peer (P2P) systems are identity based, which means that in order for one peer to trust another, it needs to know the other peer's identity. Hence, there exists an inherent tradeoff between trust and anonymity. To the best of our knowledge, there is currently no P2P protocol that provides complete mutual anonymity as well as authentication and trust management. We propose a zero-knowledge authentication scheme called pseudo trust (PT), where each peer, instead of using its real identity, generates an unforgeable and verifiable pseudonym using a one-way hash function. A novel authentication scheme based on zero-knowledge proof is designed so that peers can be authenticated without leaking any sensitive information. With the help of PT, most existing identity-based trust management schemes become applicable in mutual anonymous P2P systems. We analyze the security and the anonymity in PT, and evaluate its performance using trace-driven simulations and a prototype PT-enabled P2P network. The strengths of our design include (1) no need for a centralized trusted party or CA, (2) high scalability and security, (3) low traffic and cryptography processing overheads, and (4) man-in-middle attack resistance.
提出了一种从3轮公开掷币的对任何NP语言的诚实验证者零知识证明系统到纯公钥模型下4轮(轮最优)对同一语言的具有并发合理性的并发零知识证明系统.该转化方法有如下优点:1) 它只引起O(1)(常数个)额外的模指数运算,相比Di Crescenzo等人在ICALP 05上提出的需要((n)个额外的模指数运算的转化方法,该系统在效率上有着本质上的提高,而所需的困难性假设不变;2) 在离散对数假设下,该转化方法产生一个完美零知识证明系统.注意到Di Crescenzo等人提出的系统只具有计算零知识性质.该转化方法依赖于一个特殊的对承诺中的离散对数的3轮诚实验证者零知识的证明系统.构造了两个基于不同承诺方案的只需要常数个模指数运算的系统,这种系统可能有着独立价值.;This paper shows how to efficiently transform any 3-round public-coin honest verifier zero knowledge argument system for any language in NP into a 4 round (round-optimal) concurrent zero knowledge argument for the same language in the bare public-key model. The transformation has the following properties: 1) incurs only O(1) (small constant, about 20) additional modular exponentiations. Compared to the concurrent zero knowledge protocol proposed by Di Crescenzo and Visconti in ICALP 2005, in which their transformation requires an overhead of ((n), the protocol is significantly more efficient under the same intractability assumptions; 2) yields a perfect zero knowledge argument under DL assumption. Note that the Di Crescenzo, et al.'s argument system enjoys only computational zero knowledge property. The transformation relies on a specific 3-round honest verifier zero knowledge proof of knowledge for committed discrete log. Such protocols that require only O(1) modular exponentiations based on different kinds of commitment scheme are developed and they may be of independent interest.
Chen Su, Tiejian Luo, Wei Liu, Jinliang Song · 5 authors
In an e-Science environment, large-scale distributed resources in autonomous domains are aggregated by unified collaborative platforms to support scientific research across organizational boundaries. In order to enhance the scalability of access management, an integrated approach for decentralizing the task from resource owners to administrators on the platform is needed. We propose an extensible access management framework to meet this requirement by supporting an administrative delegation policy. This feature allows administrators on the platform to make new policies based on the original policies made by resources owners. An access protocol that merges SAML and XACML is also included in the framework. It defines how distributed parties operate with each other to make decentralized authorization decisions.
Omar Khadeer Hussain, Elizabeth Chang, Farookh Khadeer Hussain, Tharam S. Dillon · 5 authors
Risk is associated with almost every activity that is undertaken on a daily life. Risk associated with Trust, Security and Privacy. Risk is associated with transactions, businesses, information systems, environments, networks, partnerships, etc. Generally speaking, risk signifies the likelihood of financial losses, human casualties, business destruction and environmental damages. Risk indicator gives early warning to the party involved and helps avoid deserters. Until now, risk has been discussed extensively in the areas of investment, finance, health, environment, daily life activities and engineering. However, there is no systematic study of risk in Decentralised communication, which involves e-business, computer networks and service oriented environment. In this paper, we define risk associated with trusted communication in e-business and e-transactions; provide risk indicator calculations and basic application areas.