Privacy Preserving Enforcement of Sensitive Policies in Outsourced and Distributed Environments

The enforcement of sensitive policies in untrusted environments is still an open challenge for policy-based systems. On the one hand, taking any appropriate security decision requires access to these policies. On the other hand, if such access is allowed in an untrusted environment then confidential information might be leaked by the policies. The key challenge is how to enforce sensitive policies and protect content in untrusted environments. In the context of untrusted environments, we mainly distinguish between outsourced and distributed environments. The most attractive paradigms concerning outsourced and distributed environments are cloud computing and opportunistic networks, respectively. In this dissertation, we present the design, technical and implementation details of our proposed policy-based access control mechanisms for untrusted environments. First of all, we provide full confidentiality of access policies in outsourced environments, where service providers do not learn private information about policies. We support expressive policies and take into account contextual information. The system entities do not share any encryption keys. For complex user management, we offer the full-fledged Role-Based Access Control (RBAC) policies. In opportunistic networks, we protect content by specifying expressive policies. In our proposed approach, brokers match subscriptions against policies associated with content without compromising privacy of subscribers. As a result, unauthorised brokers neither gain access to content nor learn policies and authorised nodes gain access only if they satisfy policies specified by publishers. Our proposed system provides scalable key management in which loosely-coupled publishers and subscribers communicate without any prior contact. Finally, we have developed a prototype of the system that runs on real smartphones and analysed its performance.Comment: Ph.D. Dissertation. http://eprints-phd.biblio.unitn.it/1124

Toward Effective Access Control Using Attributes and Pseudoroles

Sharing of information is fundamental to modern computing environments across many application domains. Such information sharing, however, raises security and privacy concerns that require effective access control to prevent unauthorized access and ensure compliance with various laws and regulations. Current approaches such as Role-Based Access Control (RBAC), and Attribute-Based Access Control (ABAC) and their variants are inadequate. Although it provides simple administration of access control and user revocation and permission review, RBAC demands complex initial role engineering and makes access control static. ABAC, on the other hand, simplifies initial security setup and enables flexible access control, but increases the complexity of managing privileges, user revocation and user permissions review. These limitations of RBAC and ABAC have thus motivated research into the development of newer models that use attributes and policies while preserving RBAC\u27s advantages. This dissertation explores the role of attributes---characteristics of entities in the system---in achieving effective access control. The first contribution of this dissertation is the design and development of a secure access system using Ciphertext-Policy Attribute-Based Encryption (CP-ABE). The second contribution is the design and validation of a two-step access control approach, the BiLayer Access Control (BLAC) model. The first layer in BLAC checks whether subjects making access requests have the right BLAC pseudoroles---a pseudorole is a predefined subset of a subject\u27s static attributes. If requesting subjects hold the right pseudoroles, the second layer checks rule(s) within associated BLAC policies for further constraints on access. BLAC thus makes use of attributes effectively while preserving RBAC\u27s advantages. The dissertation\u27s third contribution is the design and definition of an evaluation framework for time complexity analysis, and uses this framework to compare BLAC model with RBAC and ABAC. The fourth contribution is the design and construction of a generic access control threat model, and applying it to assess the effectiveness of BLAC, RBAC and ABAC in mitigating insider threats

Optimization of Access Control Policies

Organizations undertake complex and costly projects to model high-quality Access Control Policies (ACPs). Once built, these policies must be maintained and managed in an ongoing process to keep their quality high. Insufficient maintenance leads to inaccurate authorization decisions and increases the policies’ administrative effort and susceptibility to errors. While the initial modeling of ACPs has received significant research interest, their optimization is not yet covered as broadly. This work provides a theoretical foundation for ACP quality and its optimization. Furthermore, it analyzes how existing research addresses optimization of ACPs with regard to six crucial optimization dimensions. It presents a structured literature survey tracing these optimization dimensions, the contributed research artifact and data requirements. Building on this literature catalogue, this work elaborates on inaccuracies for user permission assignments, data availability, minimal perturbation and recommendation-based optimization

Privacy-Aware and Secure Decentralized Air Quality Monitoring

Indoor Air Quality monitoring is a major asset to improving quality of life and building management. Today, the evolution of embedded technologies allows the implementation of such monitoring on the edge of the network. However, several concerns need to be addressed related to data security and privacy, routing and sink placement optimization, protection from external monitoring, and distributed data mining. In this paper, we describe an integrated framework that features distributed storage, blockchain-based Role-based Access Control, onion routing, routing and sink placement optimization, and distributed data mining to answer these concerns. We describe the organization of our contribution and show its relevance with simulations and experiments over a set of use cases

IaaS-cloud security enhancement: an intelligent attribute-based access control model and implementation

The cloud computing paradigm introduces an efficient utilisation of huge computing resources by multiple users with minimal expense and deployment effort compared to traditional computing facilities. Although cloud computing has incredible benefits, some governments and enterprises remain hesitant to transfer their computing technology to the cloud as a consequence of the associated security challenges. Security is, therefore, a significant factor in cloud computing adoption. Cloud services consist of three layers: Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). Cloud computing services are accessed through network connections and utilised by multi-users who can share the resources through virtualisation technology. Accordingly, an efficient access control system is crucial to prevent unauthorised access. This thesis mainly investigates the IaaS security enhancement from an access control point of view. [Continues.

Supporting the information systems requirements of distributed healthcare teams

The adoption of a patient-centric approach to healthcare delivery in the National Health Service (NHS) in the UK has led to changing requirements for information systems supporting the work of health and care practitioners. In particular, the patient-centric approach emphasises teamwork and cross-boundary coordination and collaboration. Although a great deal of both time and money has been invested in modernising healthcare information systems, they do not yet meet the requirements of patient-centric work. Current proposals for meeting these needs focus on providing cross-boundary information access in the form of an integrated Electronic Patient Record (EPR). This research considers the requirements that are likely to remain unmet after an integrated EPR is in place and how to meet these. Because the patient-centric approach emphasises teamwork, a conceptual model which uses care team meta-data to track and manage team members and professional roles is proposed as a means to meet this broader range of requirements. The model is supported by a proof of concept prototype which leverages team information to provide tailored information access, targeted notifications and alerts, and patient and team management functionality. Although some concerns were raised regarding implementation, the proposal was met with enthusiasm by both clinicians and developers during evaluation. However, the area of need is broad and there is still a great deal of work to be done if this work is to be taken forward.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

SLEC: A Novel Serverless RFID Authentication Protocol Based on Elliptic Curve Cryptography

Radio Frequency Identification (RFID) is one of the leading technologies in the Internet of Things (IoT) to create an efficient and reliable system to securely identify objects in many environments such as business, health, and manufacturing areas. Since the RFID server, reader, and tag communicate via insecure channels, mutual authentication between the reader and the tag is necessary for secure communication. The central database server supports the authentication of the reader and the tag by storing and managing the network data. Recent lightweight RFID authentication protocols have been proposed to satisfy the security features of RFID communication. A serverless RFID system is a new promising solution to alternate the central database for mobile RFID models. In this model, the reader and the tag perform the mutual authentication without the support of the central database server. However, many security challenges arise from implementing the lightweight RFID authentication protocols in the serverless RFID network. We propose a new robust serverless RFID authentication protocol based on the Elliptic Curve Cryptography (ECC) to prevent the security attacks on the network and maintain the confidentiality and the privacy of the authentication messages and tag information and location. While most of the current protocols assume a secure channel in the setup phase to transmit the communication data, we consider in our protocol an insecure setup phase between the server, reader, and tag to ensure that the data can be renewed from any checkpoint server along with the route of the mobile RFID network. Thus, we implemented the elliptic curve cryptography in the setup phase (renewal phase) to transmit and store the data and the public key of the server to any reader or tag so that the latter can perform the mutual authentication successfully. The proposed model is compared under the classification of the serverless model in term of computation cost and security resistance

Functionality-based application confinement: A parameterised and hierarchical approach to policy abstraction for rule-based application-oriented access controls

Access controls are traditionally designed to protect resources from users, and consequently make access decisions based on the identity of the user, treating all processes as if they are acting on behalf of the user that runs them. However, this user-oriented approach is insufficient at protecting against contemporary threats, where security compromises are often due to applications running malicious code, either due to software vulnerabilities or malware. Application-oriented access controls can mitigate this threat by managing the authority of individual applications. Rule-based application-oriented access controls can restrict applications to only allow access to the specific finely-grained resources required for them to carry out their tasks, and thus can significantly limit the damage that can be caused by malicious code. Unfortunately existing application-oriented access controls have policy complexity and usability problems that have limited their use. This thesis proposes a new access control model, known as functionality-based application confinement (FBAC). The FBAC model has a number of unique features designed to overcome problems with previous approaches. Policy abstractions, known as functionalities, are used to assign authority to applications based on the features they provide. Functionalities authorise elaborate sets of finely grained privileges based on high-level security goals, and adapt to the needs of specific applications through parameterisation. FBAC is hierarchical, which enables it to provide layers of abstraction and encapsulation in policy. It also simultaneously enforces the security goals of both users and administrators by providing discretionary and mandatory controls. An LSM-based (Linux security module) prototype implementation, known as FBAC-LSM, was developed as a proof-of-concept and was used to evaluate the new model and associated techniques. The policy requirements of over one hundred applications were analysed, and policy abstractions and application policies were developed. Analysis showed that the FBAC model is capable of representing the privilege needs of applications. The model is also well suited to automaiii tion techniques that can in many cases create complete application policies a priori, that is, without first running the applications. This is an improvement over previous approaches that typically rely on learning modes to generate policies. A usability study was conducted, which showed that compared to two widely-deployed alternatives (SELinux and AppArmor), FBAC-LSM had significantly higher perceived usability and resulted in significantly more protective policies. Qualitative analysis was performed and gave further insight into the issues surrounding the usability of application-oriented access controls, and confirmed the success of the FBAC model

A Study of Access Control for Electronic Health Records

The expansion between Information Technology and Healthcare has created many new options for both disciplines, as well as challenges. One of these topics is the Electronic Health Record (EHR) and the push for a universal record. A challenge for this topic is access control: how to keep patient’s personal health information secure, but at the same time accessible to all fields of healthcare and accomplish this within the federal privacy laws made by our government. This study focuses on the idea of a single EHR containing all the different medical information for all the areas of healthcare for a patient. This single EHR would be stored in a database and its use secured though the use of access control using a hierarchy of user groups, which would be divided into different roles to assign access privileges. This access control method would be implemented by possibly using mechanisms such as Bell-LaPadulla Model, The Strawman Design, Public/Private Key algorithms, or other methods. The first goal would be to create this structure for a single entity (e.g., One Hospital, Clinic, or Doctor’s office) and then progress to a distributed model where multiple entities can store and share information