Shangyuan Guan

Towards Automated Trust Negotiation for Grids

Trust is an important aspect of decision making for grid applications. It has been a fundamental but challenging problem to gain assurance of the trustworthiness of service providers or requesters. This paper proposes a novel trust negotiation framework, ENVOY, to establish trust relationship between service providers and requesters in grids. ENVOY supports various kinds of delegation by leveraging attribute-based credentials and defines delegation range expediently by using attribute constraint, and we develop a negotiation strategy based on protection tree to support ENVOY, which provides the support for protection of sensitive information of the two negotiation parties. Moreover, ENVOY employs multithreaded technology and trust ticket to speed up negotiation. This paper describes the implementation of ENVOY and designs experiments to evaluate its performance, and the experimental results show that it is applicable.

EntityTrust: Feedback credibility-based global reputation mechanism in cooperative computing system

Trust and reputation are important decision-making factors in cooperative computing systems. It is a fundamental but challenging task for reputation systems to estimate entitys reputation accurately and efficiently in distributed environment. We propose EntityTrust, a global reputation mechanism in cooperative computing systems. EntityTrust introduces a new direct feedback metrics to reflect the dynamic feature of trust. Besides that, an entitys feedback credibility can affect its reputation in a direct way. Experimental results show that EntityTrust can improve the accuracy and efficiency of evaluation for global reputation. Moreover, it can effectively combat malicious behaviors presented in the cooperative communities.

FORT: A decentralized automated trust negotiation framework for grids

Trust has been recognized as an important factor for grid security. This paper proposes a decentralized automated trust negotiation framework, FORT, to establish trust relationship between service providers and service requesters in grids. FORT presents many innovative features. First, FORT is decentralized, so it scales well and is well-suited for large-scale grids. Second, FORT refines its policy language with attribute constraint, so it can provide the support for effective protection of sensitive information of the two negotiation parties and flexible limitation of delegation range. Last, we employ multithreaded technology to speed up negotiation. This paper depicts the implementation of FORT and designs experiments to evaluate its performance. Experimental results show that FORT can effectively protect sensitive services at the cost of little performance of systems and is scalable.

SDRD: a novel approach to resource discovery in grid environments

Scalability and routing efficiency are two crucial aspects of resource discovery in grid environments. SDRD, a novel approach to resource discovery in grid environments, is proposed in this paper. Basic model of resource discovery is proposed. Based on the basic model, formal description of SDRD is given. Sophisticated routing strategies are implemented in SDRD to improve the scalabilities and routing efficiencies of existing peer-to-peer based discovery approaches to grid resource. Improved Distributed Hash Tables (DHTs) are adopted within virtual organizations (VOs) to achieve better local routing efficiency. SuperNodes are only in charge of forwarding requests to other SuperNodes in different VOs when the desired resources are not present in local VO, which enhances the scalability due to the lower load on SuperNodes. SDRD could be applied to other resource management models to offer excellent scalability and high routing efficiency. Results of analysis and simulations show that SDRD scales well and could offer an efficient decentralized discovery service in grid.

Automated Trust Negotiation Based on Concurrent Zero-Knowledge for e-Business Applications

Exchange of attribute certificates is a means to establish mutual trust between strangers wishing to share resources or conduct business transactions. Automated trust negotiation (ATN) is a promising approach to regulating the exchange of sensitive information during this process. It has been a fundamental but challenging problem to preserve the privacy of the two negotiation parties during the period of ATN. We present the enhanced hidden credentials and improved concurrent zero-knowledge proof protocol. Based on the above technologies, we propose an ATN for e-business applications, named CASTLE. CASTLE can not only enable the oblivious and selective usage of an attribute or a certificate, but also be resistible for many attacks, especially conspiracy attack. We illustrate the usage of CASTLE through a typical example.

CASTTE: A Trust Management for Securing the Grid

It has been a fundamental but challenging problem to gain assurance of the trustworthiness of service providers or requesters and ensure their interests. We present the formal definition of trust management, and then propose a trust management, CASTTE, to secure sensitive services and requesters in grids. CASTTE verifies access trust by using trust negotiation so as to protect sensitive services, and protects sensitive information of the two negotiators effectively by using a negotiation strategy based on protection tree. Furthermore, we utilize trust force to specify provision trust and apply trust force to service selection. This paper implements CASTTE and designs experiments to evaluate its performance. The experimental results show that it can not only protect sensitive services at the cost of little performance of systems, but also identify good services from bad ones effectively.

A Framework for Reputation Management in Large-Scale Distributed Systems

The increasing security requirements for distributed collaborations, as well as the trend toward large-scale and remote geographically-dispersed computer systems, have created a growing demand for better trustfulness evaluation of participants involved in the collaboration. We propose a novel local-weighted and global feedback-based reputation framework for reputation management to facilitate secure collaborations in large-scale distributed systems. Different from existing works, we evaluate feedback trustfulness of participants involved in the collaboration in our proposed framework. Experimental results show that our proposed framework is applicable, effective and robust in combating malicious participants and malicious behaviors in large-scale distributed systems such as peer-to-peer networks.

A Novel Automated Trust Negotiation Framework for Securing Grids

Automated Trust Negotiation (ATN) is a promising approach to allowing strangers to access sensitive services in open environments. Although many ATN systems are proposed, some issues still remain to be addressed: 1) they are centralized and cannot scale well; and 2) their policy languages are coarse-grained. To address the above problems and secure grids, we present a novel automated trust negotiation framework, FORT, to establish trust relationship between service providers and service requesters. FORT is decentralized, so it scales well. Furthermore, we utilize attribute constraints to refine its language. This paper implements FORT and designs experiments to evaluate its performance. Experimental results show that FORT can effectively protect sensitive services at the cost of little performance of systems and scale well.

A Distributed Trust Management Based on Authorizing Negotiation in Open and Dynamic Environments

Trust has been recognized as an important factor for information security in open and dynamic environments, such as Internet applications, p2p systems etc. On the basis of analyzing existing trust management systems, this paper proposes a Distributed Trust Management based on Authorizing Negotiation (DTMAN). DTMAN presents a number of innovative features. First, it can authorize strangers by using authorizing negotiation, so it is very suitable for open and dynamic environments. Second, a high efficient algorithm for compliance checking is developed to support DTMAN, whose time complexity and space complexity are both O(n) (where n is the cardinality of the set of authorization credentials). The experimental result shows that the algorithm of DTMAN is more efficient than others.