Dynamic trust models for ubiquitous computing environments

A significant characteristic of ubiquitous computing is the need for interactions of highly mobile entities to be secure: secure both for the entity and the environment in which the entity operates. Moreover, ubiquitous computing is also characterised by partial views over the state of the global environment, implying that we cannot guarantee that an environment can always verify the properties of the mobile entity that it has just received. Secure in this context encompasses both the need for cryptographic security and the need for trust, on the part of both parties, that the interaction is functioning as expected. In this paper we make a broad assumption that trust and cryptographic security can be considered as orthogonal concerns (i.e. an entity might encrypt a deliberately incorrect answer to a legitimate request). We assume the existence of reliable encryption techniques and focus on the characteristics of a model that supports the management of the trust relationships between two entities during an interaction in a ubiquitous environment

The PERMIS X.509 Based Privilege Management Infrastructure

This document describes the PERMIS X.509 Based Privilege Management Infrastructure, which is a trust management system as described in RFC 2704 [2]. The PERMIS Infrastructure is compared with the AAA Authorisation Framework described in RFC 2904 [4], and is shown to be compatible with it

Security models for trusting network appliances

A significant characteristic of pervasive computing is the need for secure interactions between highly mobile entities and the services in their environment. Moreover,these decentralised systems are also characterised by partial views over the state of the global environment, implying that we cannot guarantee verification of the properties of the mobile entity entering an unfamiliar domain. Secure in this context encompasses both the need for cryptographic security and the need for trust, on the part of both parties, that the interaction is functioning as expected. In this paper we make a broad assumption that trust and cryptographic security can be considered as orthogonal concerns (i.e. cryptographic measures do not ensure transmission of correct information). We assume the existence of reliable encryption techniques and focus on the characteristics of a model that supports the management of the trust relationships between two devices during ad-hoc interactions

Dynamic User Role Assignment in Remote Access Control

The Role-Based Access Control (RBAC) model has been widely applied to a single domain in which users are known to the administrative unit of that domain, beforehand. However, the application of the conventional RBAC model for remote access control scenarios is not straightforward. In such scenarios, the access requestor is outside of the provider domain and thus, the user population is heterogeneous and dynamic. Here, the main challenge is to automatically assign users to appropriate roles of the provider domain. Trust management has been proposed as a supporting technique to solve the problem of remote access control. The key idea is to establish a mutual trust between the requestor and provider based on credentials they exchange. However, a credential doesn't convey any information about the behavior of its holder during the time it is being used. Furthermore, in terms of privileges granted to the requestor, existing trust management systems are either too restrictive or not restrictive enough. In this paper, we propose a new dynamic user-role assignment approach for remote access control, where a stranger requests for access from a provider domain. Our approach has two advantages compared to the existing dynamic user-role assignment techniques. Firstly, it addresses the principle of least privilege without degrading the efficiency of the access control system. Secondly, it takes into account both credentials and the past behavior of the requestor in such a way that he cannot compensate for the lack of necessary credentials by having a good past behavior

Shinren : Non-monotonic trust management for distributed systems

The open and dynamic nature of modern distributed systems and pervasive environments presents significant challenges to security management. One solution may be trust management which utilises the notion of trust in order to specify and interpret security policies and make decisions on security-related actions. Most trust management systems assume monotonicity where additional information can only result in the increasing of trust. The monotonic assumption oversimplifies the real world by not considering negative information, thus it cannot handle many real world scenarios. In this paper we present Shinren, a novel non-monotonic trust management system based on bilattice theory and the anyworld assumption. Shinren takes into account negative information and supports reasoning with incomplete information, uncertainty and inconsistency. Information from multiple sources such as credentials, recommendations, reputation and local knowledge can be used and combined in order to establish trust. Shinren also supports prioritisation which is important in decision making and resolving modality conflicts that are caused by non-monotonicity

Interoperability, Trust Based Information Sharing Protocol and Security: Digital Government Key Issues

Improved interoperability between public and private organizations is of key significance to make digital government newest triumphant. Digital Government interoperability, information sharing protocol and security are measured the key issue for achieving a refined stage of digital government. Flawless interoperability is essential to share the information between diverse and merely dispersed organisations in several network environments by using computer based tools. Digital government must ensure security for its information systems, including computers and networks for providing better service to the citizens. Governments around the world are increasingly revolving to information sharing and integration for solving problems in programs and policy areas. Evils of global worry such as syndrome discovery and manage, terror campaign, immigration and border control, prohibited drug trafficking, and more demand information sharing, harmonization and cooperation amid government agencies within a country and across national borders. A number of daunting challenges survive to the progress of an efficient information sharing protocol. A secure and trusted information-sharing protocol is required to enable users to interact and share information easily and perfectly across many diverse networks and databases globally.Comment: 20 page

Integrity Constraints in Trust Management

We introduce the use, monitoring, and enforcement of integrity constraints in trust management-style authorization systems. We consider what portions of the policy state must be monitored to detect violations of integrity constraints. Then we address the fact that not all participants in a trust management system can be trusted to assist in such monitoring, and show how many integrity constraints can be monitored in a conservative manner so that trusted participants detect and report if the system enters a policy state from which evolution in unmonitored portions of the policy could lead to a constraint violation.Comment: An extended abstract appears in the proc. of the 10th ACM Symp. on Access Control Models and Technologies (SACMAT). 200

Privacy, security, and trust issues in smart environments

Recent advances in networking, handheld computing and sensor technologies have driven forward research towards the realisation of Mark Weiser's dream of calm and ubiquitous computing (variously called pervasive computing, ambient computing, active spaces, the disappearing computer or context-aware computing). In turn, this has led to the emergence of smart environments as one significant facet of research in this domain. A smart environment, or space, is a region of the real world that is extensively equipped with sensors, actuators and computing components [1]. In effect the smart space becomes a part of a larger information system: with all actions within the space potentially affecting the underlying computer applications, which may themselves affect the space through the actuators. Such smart environments have tremendous potential within many application areas to improve the utility of a space. Consider the potential offered by a smart environment that prolongs the time an elderly or infirm person can live an independent life or the potential offered by a smart environment that supports vicarious learning

Codex Enables Secure Offline Micropayments

This paper introduces a new micropayment scheme, suitable for all kinds of transactions, and does not require online transactions for either the payer or payee. The designed method uses an encrypted data structure called Codex which self replicates to represent the current values of both the payer and the payee. The model, while providing fraud detection also guarantees payment & loss recovery