Trust Establishment in Pervasive Grid Environments Syed Naqvi, Michel Riguidel TÉLÉCOM PARIS ÉNST É cole N ationale S upérieur des T élécommunications (ENST) 46 Rue Barrault, Paris 75013, France {naqvi,

22 November 2005CGW'05 - Krakow, Poland2 Outline Introduction Trust Establishment Implementation Status Conclusions

22 November 2005CGW'05 - Krakow, Poland3 Outline Introduction Trust Establishment Implementation Status Conclusions

22 November 2005CGW'05 - Krakow, Poland4 The reliance on a property or a virtue of a person, or the conviction that a given premise is true. Oxford Dictionary An entity A is considered to trust another entity B when entity A believes that entity B will behave exactly as expected and required. International Telecommunication Union Trust

Pervasive Grid Environments The Grid can be accessed from any networked device –laptop, mobile phone, PDA, … The Grid can be composed of Internet-connected light- weight devices –Inherent limitations of these devices, physical security, … Ubiquitous access to the computing and storage resources –Adaptable to users’ environments; available anywhere anytime –Enable mobile users to launch, monitor, and steer applications on the Grid Introduces new challenges –Bandwidth, heterogeneity, connectivity, scalability, interfacing –Security: physical; gaps; requires knowledge of context and state

22 November 2005CGW'05 - Krakow, Poland6 The Problem Statement How pervasive grid nodes can trust unknown infrastructure with their private data; and How a computing infrastructure can trust a mobile node which is seeking access to its resources.

22 November 2005CGW'05 - Krakow, Poland7 Outline Introduction Trust Establishment Implementation Status Conclusions

8 Trust Requirements Identification, Access Control, Privacy, … User-based Trust Relationships –If a user has the right to use sites A and B, the user should be able to use sites A and B together without requiring the security administrators from sites A and B to interact. Distributed Trust Evaluation –The decentralized nature of administration makes it difficult to establish and propagate trust. A distributed trust evaluation scheme is therefore required for the pervasive grid environments. Non-History-based Trust Establishment –If there is no trust among parties and there is no mechanism to build some trust based on a history of previous interactions.

22 November 2005CGW'05 - Krakow, Poland9 Delegation of trust –Decentralized hierarchical administration, scalability of certificate issuing capacity, … Continuous monitoring of the changes to the trust level of each node –Dynamic evaluation of the trust relationships, broadcast the presence of a malicious node in the environment, … Consideration of context and state –Determination of the access control on the basis of user’s location and the state of the user’s environment. Trust Establishment Approach

22 November 2005CGW'05 - Krakow, Poland10 Instead of having a single value representing the trust- worthiness of a node, the value should be broken into separate attributes – confidences –Each confidence represents a characteristic of a node from which trust can be synthesized. For example: We can trust a node to be accurate (important for data integrity) We can trust a node to complete task reliably We can trust nodes to return data quickly (or always in the guaranteed time). These attributes form a virtual plane to link the resources, users (individuals & services) and the applications –Virtual and extensible basis for synthesizing varying types of trust Signifies that there is not a fix form of trust among the various entities Allows the greatest flexibility from one entity to the other

22 November 2005CGW'05 - Krakow, Poland11 From the functional point of view: –Attribute certificates are used in compliment with identity certificates provided by the existing infrastructure. Identity certificates are used to verify the identity of an entity in a highly anonymous environment (e.g. the internet) Attribute certificates are used to determine the trustworthiness of an uncertain environment (such as Pervasive Grid) –For direct trust relationship within a single domain, a node estimates the trustworthiness of the node it is going to interact. By using the centralized credentials architecture to determine the trust values of the individual nodes. By maintaining a trust table of the domain. –For indirect trust relationships across multiple domains, a node has to trust all the intermediaries that it traversed before arriving the second node. By evaluating the trust degree along the whole path.

22 November 2005CGW'05 - Krakow, Poland12 Outline Introduction Trust Establishment Implementation Status Conclusions

22 November Exam Hall Library CA / Storage & Display Center S SSS T T S S Experimental Set-up

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22 November 2005CGW'05 - Krakow, Poland16 The computing world is moving from the desktop computing to the mobile and nomadic computing. The near future Grid users will prefer to access the grid resources from their smart devices. Current research efforts to address trust problem in a Grid environment focus on relatively static scenarios. Pervasive Grid Environments require dynamic establishment of trust. These pervasive Grid environments may be few years ahead but its important to envision how things will be dealt with in the future. Our future directions include: –Implementation of deeper and fine grained interactions among the various entities of the Pervasive Grid Environments. –Implementation of our trust model as an extension to the GSI.

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