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Many languages and algebras have been proposed in recent years for the specification of authorization policies. For some proposals, such as XACML, the main motivation is to address real-world requirements , typically by providing a complex policy language with somewhat informal evaluation methods; others try to provide a greater degree of formality –(More)
Component based development allows to build software upon existing components and promises to improve software reuse and reduce costs. To gain reliability of a component based system, verification technologies such as testing can be applied to check underlying components and their composition. Conformance testing checks the consistency between the behavior(More)
the governments of the People's Republic of China and Portugal through a contribution to the UNU Endowment Fund. As well as providing two-thirds of the endowment fund, the Macao authorities also supply UNU-IIST with its office premises and furniture and subsidise fellow accommodation. The mission of UNU-IIST is to assist developing countries in the(More)
This paper addresses the making of security decisions, such as access-control decisions or spam filtering decisions, under uncertainty, when the benefit of doing so outweighs the need to absolutely guarantee these decisions are correct. For instance, when there are limited, costly, or failed communication channels to a policy-decision-point. Previously,(More)
Attribute-based Access Control (ABAC) extends traditional Access Control by considering an access request as a set of pairs attribute name-value, making it particularly useful in the context of open and distributed systems, where security relevant information can be collected from different sources. However, ABAC enables attribute hiding attacks, allowing(More)