In recent years, Peer-to-Peer (P2P) systems and computational Grids are evolving into a new distributed computing model, called P2P Grid. This paper presents a new approach to solving the trust and security problems in a P2P Grid. Establishing trust in P2P Grids is essential to build lasting working relationships among the peers joining collective Grid applications. A P2P reputation system is t...

The foundational model of conjoint analysis is to model consumer purchase preferences by means of utility functions. Analysts run surveys and interviews to obtain a basic set of training data, typically user preferences on which the utility function is mapped. The utility theory trust the training data as knowledge while there is large literature emphasizing that users preference may change, ma...

In peer-to-peer networks, free riding is a major problem. Reputation management systems can be used to overcome this problem. Reputation estimation methods generally do not considers the uncertainties in the inputs. We propose a reputation estimation method using BLUE (Best Linear Unbiased estimator) estimator that consider uncertainties in the input variables. Reputation aggregation in peer to...

Obtaining user opinion (using votes) is essential to ranking user-generated online content. However, any content voting system is susceptible to the Sybil attack where adversaries can out-vote real users by creating many Sybil identities. In this paper, we present SumUp, a Sybilresilient vote aggregation system that leverages the trust network among users to defend against Sybil attacks. SumUp ...

Perez, Carlos R. M.S.E.C.E., Purdue University, December, 2007. Reputation-based Resilient Data Aggregation in Sensor Network . Major Professor: Saurabh Bagchi. Data aggregation, or the fusing of many sensor measurements into a single summary, has been proposed as an important primitive in wireless sensor networks. But data aggregation is vulnerable to security attacks and natural failures wher...

Location-Based Services are emerging fast and the problems with privacy are growing with them. While a platform for Location-Based Services can provide the user with high-quality Location-Based Service browsing and powerful mechanisms to reduce the amount of location data transmitted such a platform is dangerous as it has to manage the location data of the users and the actual service usage. Th...

While web applications provide enormous opportunities, they also present potential threats and risks due to a lack of trust among users. Reputation systems provide a promising way for building trust through social control by harnessing the community feedback in the form of feedback. However, reputation systems also introduce vulnerabilities due to potential manipulations by dishonest or malicio...

Location-Based Services are emerging fast and the problems with privacy are growing with them.While a platform for Location-Based Services can provide the user with high-quality Location-Based Service browsing and powerful mechanisms to reduce the amount of location data transmitted such a platform is dangerous as it has to manage the location data of the users and the actual service usage. Thi...

In the context of an increasing demand for data and computational services, the benefits of cloud computing are substantial. However, cloud computing capabilities (as currently provisioned) can prove limited when accessed through a single provider. Extending capabilities of clouds by using user owned and provisioned devices can address a number of challenges arising in the context of current cl...

This paper addresses the problem of pay-as-you-watch services over unicast and multicast communications. For each communication model, we present two solutions, non-verifiable and verifiable, depending on the existence or non-existence of trust between the source and the receiver(s). In verifiable schemes, the source obtains a proof of correct reception by the receiver(s); in non-verifiable sch...