Combining behavioural types with security analysis

Today's software systems are highly distributed and interconnected, and they increasingly rely on communication to achieve their goals; due to their societal importance, security and trustworthiness are crucial aspects for the correctness of these systems. Behavioural types, which extend data types by describing also the structured behaviour of programs, are a widely studied approach to the enforcement of correctness properties in communicating systems. This paper offers a unified overview of proposals based on behavioural types which are aimed at the analysis of security properties

Decision Support Tools for Cloud Migration in the Enterprise

This paper describes two tools that aim to support decision making during the migration of IT systems to the cloud. The first is a modeling tool that produces cost estimates of using public IaaS clouds. The tool enables IT architects to model their applications, data and infrastructure requirements in addition to their computational resource usage patterns. The tool can be used to compare the cost of different cloud providers, deployment options and usage scenarios. The second tool is a spreadsheet that outlines the benefits and risks of using IaaS clouds from an enterprise perspective; this tool provides a starting point for risk assessment. Two case studies were used to evaluate the tools. The tools were useful as they informed decision makers about the costs, benefits and risks of using the cloud.Comment: To appear in IEEE CLOUD 201

CREATe 2012-2016: Impact on society, industry and policy through research excellence and knowledge exchange

On the eve of the CREATe Festival May 2016, the Centre published this legacy report (edited by Kerry Patterson & Sukhpreet Singh with contributions from consortium researchers)

Short Paper: Blockcheck the Typechain

Recent efforts have sought to design new smart contract programming languages that make writing blockchain programs safer. But programs on the blockchain are beholden only to the safety properties enforced by the blockchain itself: even the strictest language-only properties can be rendered moot on a language-oblivious blockchain due to inter-contract interactions. Consequently, while safer languages are a necessity, fully realizing their benefits necessitates a language-aware redesign of the blockchain itself. To this end, we propose that the blockchain be viewed as a typechain: a chain of typed programs-not arbitrary blocks-that are included iff they typecheck against the existing chain. Reaching consensus, or blockchecking, validates typechecking in a byzantine fault-tolerant manner. Safety properties traditionally enforced by a runtime are instead enforced by a type system with the aim of statically capturing smart contract correctness. To provide a robust level of safety, we contend that a typechain must minimally guarantee (1) asset linearity and liveness, (2) physical resource availability, including CPU and memory, (3) exceptionless execution, or no early termination, (4) protocol conformance, or adherence to some state machine, and (5) inter-contract safety, including reentrancy safety. Despite their exacting nature, typechains are extensible, allowing for rich libraries that extend the set of verified properties. We expand on typechain properties and present examples of real-world bugs they prevent

Obligations of trust for privacy and confidentiality in distributed transactions

Purpose – This paper aims to describe a bilateral symmetric approach to authorization, privacy protection and obligation enforcement in distributed transactions. The authors introduce the concept of the obligation of trust (OoT) protocol as a privacy assurance and authorization mechanism that is built upon the XACML standard. The OoT allows two communicating parties to dynamically exchange their privacy and authorization requirements and capabilities, which the authors term a notification of obligation (NoB), as well as their commitments to fulfilling each other's requirements, which the authors term signed acceptance of obligations (SAO). The authors seek to describe some applicability of these concepts and to show how they can be integrated into distributed authorization systems for stricter privacy and confidentiality control. Design/methodology/approach – Existing access control and privacy protection systems are typically unilateral and provider-centric, in that the enterprise service provider assigns the access rights, makes the access control decisions, and determines the privacy policy. There is no negotiation between the client and the service provider about which access control or privacy policy to use. The authors adopt a symmetric, more user-centric approach to privacy protection and authorization, which treats the client and service provider as peers, in which both can stipulate their requirements and capabilities, and hence negotiate terms which are equally acceptable to both parties. Findings – The authors demonstrate how the obligation of trust protocol can be used in a number of different scenarios to improve upon the mechanisms that are currently available today. Practical implications – This approach will serve to increase trust in distributed transactions since each communicating party receives a difficult to repudiate digitally signed acceptance of obligations, in a standard language (XACML), which can be automatically enforced by their respective computing machinery. Originality/value – The paper adds to current research in trust negotiation, privacy protection and authorization by combining all three together into one set of standardized protocols. Furthermore, by providing hard to repudiate signed acceptance of obligations messages, this strengthens the legal case of the injured party should a dispute arise