Digital Provenance Techniques and Applications

In this disseration we propose semi-automated top-down policy engineering approaches for attribute-based access control (ABAC) development. Further, we propose a hybrid ABAC policy engineering approach to combine the benefits and address the shortcomings of both top-down and bottom-up approaches. In particular, we propose three frameworks: (i) ABAC attributes extraction, (ii) ABAC constraints extraction, and (iii) hybrid ABAC policy engineering. Attributes extraction framework comprises of five modules that operate together to extract attributes values from natural language access control policies (NLACPs); map the extracted values to attribute keys; and assign each key-value pair to an appropriate entity. For ABAC constraints extraction framework, we design a two-phase process to extract ABAC constraints from NLACPs. The process begins with the identification phase which focuses on identifying the right boundary of constraint expressions. Next is the normalization phase, that aims at extracting the actual elements that pose a constraint. On the other hand, our hybrid ABAC policy engineering framework consists of 5 modules. This framework combines top-down and bottom-up policy engineering techniques to overcome the shortcomings of both approaches and to generate policies that are more intuitive and relevant to actual organization policies. With this, we believe that our work takes essential steps towards a semi-automated ABAC policy development experience.

We describe a method that centrally manages Attribute-Based Access Control (ABAC) policies and locally computes and enforces decisions regarding those policies for protection of resource repositories in host systems using their native Access Control List (ACL) mechanisms. The method is founded on the expression of an ABAC policy that conforms to the access control rules of an enterprise and leverages the ABAC policy expression by introducing representations of local host repositories into the ABAC policy expression as objects or object attributes. Repositories may be comprised of individual files, directories, or other resources that require protection. The method further maintains a correspondence between the ABAC representations and repositories in local host systems. The method also leverages an ability to conduct policy analytics in such a way as to formulate ACLs for those representations in accordance with the ABAC policy and create ACLs on repositories using the ACLs of their corresponding representations. As the ABAC policy configuration changes, the method updates the ACLs on affected representations and automatically updates corresponding ACLs on local repositories. Operationally, users attempt to access resources in local host systems, and the ABAC policy is enforced in those systems in terms of their native ACLs.

We present a new approach to the attestation of a computer's trustworthiness that is founded on provenance data of its key components. The prevailing method of attestation relies on comparing integrity measurements of the key components of a computer against a reference database of trustworthy integrity measurements. An integrity measurement is obtained by passing a software binary or any component through a hash function but this value carries little information unless there is a reference database. On the other hand, the semantics of provenance contain more details. There are expressive information such as the component's history and its causal dependencies with other elements of a computer. Hence, we argue that provenance data can be used as evidence of trustworthiness during attestation. In this paper, we describe a complete design for provenance-based attestation. The design development is guided by goals and it covers all the phases of this approach. We discuss about collecting provenance data and using the PROV data model to represent provenance data. To determine if provenance data of a component can provide evidence of its trustworthiness, we have developed a rule specification grammar and provided a discourse on using the rules. We then build the key mechanisms of this form of attestation by exploring approaches to capture provenance data and look at transforming the trust evaluation rules to XQuery language before running the rules against an XML based record of provenance data. Finally, the design is analyzed using threat modelling.

The Sustainable Development Goals (SDGs) established to be achieved by 2030 are an ensemble of 17 goals to address global environmental and social economic concerns [1]. SDG 15 concerns the protection of terrestrial ecosystems to halt biodiversity loss. Target 15.9 states that by 2020, ecosystem and biodiversity values should be integrated into national and local planning, and is related to Aichi Biodiversity Target 2 of the Strategic Plan for Biodiversity 2011-2020, which also involves integrating biodiversity values into national accounting and reporting systems [2]. The importance of maintaining ecosystem integrity is becoming widely recognized, not only to halt biodiversity loss, but also to preserve Nature’s benefits to human well-being, and has been included in many other targets such as the EU 2020 Biodiversity Strategy’s target 2, which requires the restoration of at least 15% of degraded ecosystems as well as the establishment of green infrastructures to enhance ecosystem services (ES) [3]. The Green Infrastructures (GI) framework is used as a policy tool and promotes the multi-functional use of landscapes to improve biodiversity conservation and benefits to society. It is formulated as a “strategically planned network of natural and semi-natural areas” [4] and is based on three main pillars: key habitats for target species, connectivity and ES [5]. As part of ERA-PLANET’s GEOEssential project (Essential Variables workflows for resource efficiency and environmental management), our study aims at demonstrating how the GI framework can be implemented at any geographical area or time-period through reproducible modeling workflows from field data to Essential Variables (EV) data products and policy relevant indicators to monitor and inform advances towards environmental targets. A proof of concept workflow was already set in place for computing the indicator 15.1.2: Proportion of important sites for terrestrial and freshwater biodiversity that are covered by protected areas, by ecosystem, while other workflows will follow. The execution platform is the GEOEssential Virtual Laboratory, a cloud-based virtual platform which enables access to, and execution of workflows for the ecosystem science community of practice and even more. REFERENCES: 1. UNSD, 2016. Sustainable Development Goals Report. https://unstats.un.org/sdgs/report/2016/ (accessed 18 May 2018). 2. CBD Secretariat, 2010. The Strategic Plan for Biodiversity 2011-2020, and the Aichi Biodiversity Targets. Secretariat of the Convention on Biological Diversity, Nagoya. 3. European Commission, 2011. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions - Our life insurance, our natural capital: an EU biodiversity strategy to 2020, Brussels. 4. European Commission, 2013. Green infrastructure (GI) - Enhancing Europe’s Natural Capital, Brussels. 5. Liquete, C., Kleeschulte, S., Dige, G., Maes, J., Grizzetti, B., Olah, B., & Zulian, G., 2015. Mapping green infrastructure based on ecosystem services and ecological networks: A Pan-European case study. Environmental Science & Policy, 54, 268–280.

Access control policies are crucial for establishing a secure access control system and are fundamentally based on access control models such as attribute-based access control (ABAC). Moreover, the execution of business process instances is generally recorded within an event log. It is essential to ensure conformance with ABAC policies for the event log at the time of post-execution. To conduct conformance testing of ABAC policies in business process event logs, formalizing these ABAC policies is necessary. However, the formalization is typically carried out manually, which leads to inefficiencies, low maintainability, a high likelihood of errors, and difficulty in detecting the errors. Also, there has been a notable lack of an access control metamodel to support the formalization and conformance testing of ABAC policies, as well as insufficient attention to constructing ABAC policies from existing process logs. This paper presents a model-driven workflow for significantly automating the formalization and conformance testing of ABAC policies in process logs. By leveraging a novel ABAC metamodel and its reusable patterns, the approach addresses the aforementioned issues, demonstrating effectiveness through experiments on a real-world process log.

Access control policies are dynamic in nature, and therefore require frequent updates to synchronize with the latest organizational security requirements. As these updates are handled, it is important that all user access requests be answered contemporaneously and correctly without any interruption or delay. In this paper, considering the context of Attribute Based Access Control (ABAC), we propose an approach that is capable of immediately materializing any update to the policy and ensuring that it is taken into account for any subsequent access requests. One possibility is to update the policy based on the incoming changes through ABAC policy mining techniques. However, it turns out that no existing mining approach can offer correct enforcement of policies when access requests are entertained during the updates. We provide a formal proof for this surprising result and then propose an approach called δwOP that does not suffer from this problem. Essentially, δwOP keeps track of the needed information from updates and uses this in conjunction with the existing ABAC policy rules to make access decisions. We present the complexity analysis as well as a comprehensive experimental evaluation to demonstrate the efficacy of the proposed approach for different types of changes.

This report documents the program and the outcomes of Dagstuhl Seminar 12091 ``Principles of Provenance''. The term ``provenance'' refers to information about the origin, context, derivation, ownership or history of some artifact. In both art and science, provenance information is crucial for establishing the value of a real-world artifact, guaranteeing for example that the artifact is an original work produced by an important artist, or that a stated scientific conclusion is reproducible. Since it is much easier to copy or alter digital information than it is to copy or alter real-world artifacts, the need for tracking and management of provenance information to testify the value and correctness of digital information has been firmly established in the last few years. As a result, provenance tracking and management has been studied in many settings, ranging from databases, scientific workflows, business process modeling, and security to social networking and the Semantic Web, but with relatively few interaction between these areas. This Dagstuhl seminar has focused on bringing together researchers from the above and other areas to identify the commonalities and differences of dealing with provenance; improve the mutual understanding of these communities; and identify main areas for further foundational provenance research.

This paper describes SWfPS, an architecture that aims to interact with Scientific Workflow Management Systems in order to capture and manipulate provenance metadata. For this purpose, SWfPS adopts an approach based on an abstract model for representing the lineage. This model, called Open Provenance Model, allows SWfPS to set up a homogeneous and interoperable infrastructure for handling provenance metadata. As a result, SWfPS is able to provide a framework for query metadata provenance generated in an e-Science scenario. Moreover, the architecture uses semantic web technology in order to process provenance queries. In this context, using ontologies and inference engines, SWfPS can make inferences about lineage and, based on those inferences, obtain important results from the extraction of information from the managed data, beyond what is explicitly registered.

Proliferation of smart, connected devices brings new challenges to data access and privacy control. Fine grained access control policies are typically complex, hard to maintain and tightly bound to the internal structure of the processed information. We thus discuss how semantic inference can be used together with an intuitive ontology management tool to ease the management of Attribute Based Access Control policies, even by users not experienced with semantic technologies.

Data federations allow the contents of multiple source databases to be accessed in a consistent manner. Since each source database is typically administered independently, heterogeneity often results, both in terms of how data is represented (i.e., the database schema), and in how controlled access to data is regulated. Typically, each data source exports data in relational format where it is combined into a semi-structured representation (e.g., XML). In this thesis, we address two aspects of securing heterogeneous data federations. The first deals with the accurate translation of access control policies specified over source databases into a single, unified access control policy applicable to the wider data federation. Such a translation involves mapping each local identity to one or federated identities, and ensuring that the semantics of each original source policy are preserved (i.e., that no federated identity receives access to a larger region of federated data than intended by any source policy). We outline an efficient algorithm for automating policy translation. We also underscore the importance of automated translation methods by showing that in many realistic scenarios, verifying that a federated policy satisfies all source policies is intractable. Finally, we contribute an algorithm for minimizing the size of a translated policy. The second problem we address is the prevention of information disclosures at the federated level. A disclosure risk is present when a user is able to combine the result of one or more allowable queries (i.e., queries which are permitted under the federated access control policy) with prior background knowledge in order to obtain a sufficiently high certainty of the answer to a disallowed query. We classify potential disclosure risks based on whether they can be detected at database design-time, or only when the contents of the database are known. We also describe a new measure for evaluating the magnitude of instance-based disclosure risks at query-time. Finally, we discuss the implementation of a prototype system, and conduct experiments that demonstrate the effectiveness and scalability of the proposed solution.

One of the main requirements for providing software security is the enforcement of access control policies which aim to protect resources of the system against unauthorized accesses. Any error in the implementation of such policies may lead to undesirable outcomes. For testing the implementation of access control policies, it is preferred to use automated methods which are faster and more reliable. Although several researches are conducted for automated testing of the specification of access control policies at the design phase, there is not enough research on testing their implementation. In addition, since access control is amongst non-functional requirements of the system, it is not easy to test them along with other requirements of the system by usual methods. To address this challenge, in this paper, we propose an automated method for testing the implementation of access control in a system. This method, as a model based technique, is able to extract test cases for evaluating the access control policies of the system under test. To generate test cases automatically, a combination of behavior model of the system and the specification of access control policies are used. The experimental results show that the proposed approach is able to find the failures and cover most of the code that is related to access control policies.

Documents best practice in supporting practice research works at other HE institutions including; policy, definitions, vocabulary options, metadata, workflows, repository advice and features, digitisation offers, case studies and advocacy. Report collated through visits to Goldsmiths and University of Creative Arts, conference calls to University of Westminster and Glasgow School of Arts and desk research of other UK and Australian HE Institutions.

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It is difficult to manage hybrid workflow distributed on public and private machines, a very common situation that Earth scientists face today in cloud era. Geoweaver is a efficient tool to solve that problem. Unlike other Workflow Manage Systems, Geoweaver promises to be friendly to beginners, requires little setup time, track all the provenance of the old runs, and sustain the workflow for longer even after the original used computational resources are reallocated. This presentation was given at the Earth Science Information Partners (ESIP) Summer Meeting held online in July 2020.

In computer security, many researches have tackled on the possibility of a unified model of access control, which could enforce any access control policies within a single unified system. One issue that must be considered is the efficiency of such systems, i.e., what is the computational complexity for the enforce ability validation of access control rules of a system that is capable of implementing any access control policy? We investigate this question by arguing that two fundamental requirements exist for any such system: satisfiability of access rules and ensuring absence of deadlock among rules. We then show that both of these problems are NP-complete by using some basic computational theorems applied to the components of the generic access control process.