One of the aspects of autonomic computing is self-protecting where systems are required to consistently enforce security policies in order to allow legitimate actions. The information that comes through the feedback loop after being monitored and analayzed tells the systems what is happening in the environments. The analyzed information describes situation and it is called context. The challeng...

Consider a database where each record has different access control policies. These policies could be attributes, roles, or rights that the user needs to have in order to access the record. Here we provide a protocol that allows the users to access the database record while: (1) the database does not learn who queries a record; (2) the database does not learn which record is being queried, nor t...

We present a formal (model-based) approach to describing and analysing access control policies. This approach allows us to evaluate access requests against policies, compare versions of policies with each other and check policies for internal consistency. Access control policies are described using VDM, a statebased formal modelling language. Policy descriptions are concise and may be easily ma...

This report details the progression of research conducted on my PhD, for the first half of the academic year 2006-2007. I present my intial exploration and the subsequent chosen direction of my thesis, a review of literature surrounding the subject and a summary of the work conducted to date. Furthermore, I detail the intended future progression of my research, its desired goals, proposed conte...

Access control is the process of mediating every request to data and services maintained by a system and determining whether the request should be granted or denied. Expressiveness and flexibility are top requirements for an access control system together with, and usually in conflict with, simplicity and efficiency. In this paper, we discuss the main desiderata for access control systems and i...

Solutions like SELinux have recently regenerated interest toward Mandatory Access Control (MAC) models. The role of MAC models can be expected to increase in modern systems, which are exposed to significant threats and manage high-value resources, due to the stronger protection they are able to offer. Android is a significant representative of these novel systems and the integration of MAC mode...

Data protection within information systems is one of the main concerns in computer systems security and different access control policies can be used to specify the access requests that should be granted or denied. These access control mechanisms should guarantee that information can be accessed only by authorized users and thus prevent all information leakage. We propose a methodology for spec...

Many data stream processing systems are increasingly being used to support applications that handle sensitive information, such as credit card numbers and locations of soldiers in battleground [1,2,3,6]. These data have to be protected from unauthorized accesses. However, existing access control models and mechanisms cannot be adequately adopted on data streams. In this paper, we propose a nove...

Although the notion of negotiation has been used extensively in secure communication protocols to establish common keying states, protocol modes and services, this notion is only now emerging in the area of access control policies. In this paper, we review the motivation for access policy negotiation and we provide some examples of use in practice. In particular, we illustrate the meaning, the ...

The use of languages based on positive or negative expressiveness is very common for the deployment of security policies (i.e., deployment of permissions and prohibitions on firewalls through singlehanded positive or negative condition attributes). Although these languages may allow us to specify any policy, the single use of positive or negative statements alone leads to complex configurations...