We introduce a new lightweight Symmetric Threshold Predicate Encryption (STPE) scheme, which expands the definition of Predicate Encryption. In STPE, the recipient’s private key evaluates only k predicates instead of all predicates on the sender’s encrypted data. The recipient can decrypt the data if at least k predicates are satisfied. As a new building block, we design a Content-Filtered Encryption (CFE) scheme based on STPE, which allows the sender to encrypt the message with the extracted words and the recipient to generate a filter with abusive words. The recipient can decrypt the message if the evaluation of extracted words and abusive words does not intersect more than a threshold k, where k is a flexible limit of sensitive words the recipient can accept. Otherwise, the recipient can refuse to read the message. It is essential for the recipient to generate a filter of abusive words beforehand; the incoming encrypted message will be delivered only if it bypasses this filter. Therefore, our proposed scheme enables secure filtering of words in the end-to-end encryption messaging protocol, which achieves selective security and efficiency for all communication devices. We prove that our STPE and CFE schemes are secure under the selected security assumptions. Furthermore, by utilizing the Pseudo-Random Function and XOR gate, our construction achieves lightweight computation, which benefits from the primitives of symmetric crypto mechanisms. We experimented on multiple devices, such as PCs and mobile devices. Additionally, our work demonstrates the feasibility across heterogeneous devices.

Within the context of self directed learning via the Internet, the on-going ARTyFACTS Learning Environment research project under development at the Learning Technology Research Institute, University of North London explores different ways of re-exhibiting 3D objects virtually. This multimedia facility will ultimately help remote students in their studies, the disabled person who cannot access the work, or a person who cannot travel to see the work. We describe aspects of the extension of our prototype ARTyFACTS Learning Environment. The prototype was evaluated by Architectural students at UNITEC Institute of Technology, Auckland, New Zealand, who provided positive feedback in terms of usability and utility.

Today, scientists and engineers are exploring advanced applications and uses of immersive systems that can be cost-effectively applied in their fields. However, one of the impediments to the widespread use of these technologies is the extensive technical expertise required of application developers. A software environment that provides abstractions from specific details of hardware configurations and low-level software tools is needed to provide a common base for the prototyping, development, testing and debugging of applications. This paper describes VR Juggler, a virtual platform for the creation and execution of immersive applications, that provides a virtual reality system-independent operating environment. We focus on the approach taken to specify, design and implement VR Juggler and the benefits derived from our approach.

Virtual reality (VR) installations are often unique; every one is a complex blend of hardware devices, displays and computing resources. The configuration of VR software is therefore a difficult and time-consuming process. VR Juggler, our toolkit for VR application development, addresses these problems with a number of innovations. VR Juggler provides a unique system for organizing the configuration information for a system and minimizing the proliferation of configuration files that many systems suffer. It provides a graphical tool, called VjControl, for editing configurations, which can protect users from many common mistakes. VR Juggler also has advanced capabilities for monitoring and altering the configuration of a running immersive application.