A Semantic Framework for Mode Change Protocols

We present a unified framework for the specification and analysis of mode-change protocols used in multi-mode realtime systems. We propose a highly expressive formalism, called MCP, to model the system behavior during mode transitions, and show how various existing mode change protocols can be described as MCPs. The explicit representation of the MCP model provides a means to analyze the system state during a mode transition as well as during an intra-mode execution. We introduce the concept of feasibility with respect to the MCP model, and give a decidable method for checking the feasibility of a MCP for a given multi-mode system. The formalization of mode change behaviors using the MCP model allows a range of mode change protocols to be modeled, evaluated, and optimized to the specific operations and performance requirements of the system. Besides feasibility analysis, it is also possible to analyze other system behaviors (e.g., delay between modes, buffer backlog) using automata verification techniques. Our framework can also be used to describe mode change semantics of multi-mode systems whose modes/transitions have different criticality levels, or of systems composed of multiple multi-mode components that require different mode change protocols

Term-based composition of security protocols

In the context of security protocol parallel composition, where messages belonging to different protocols can intersect each other, we introduce a new paradigm: term-based composition (i.e. the composition of message components also known as terms). First, we create a protocol specification model by extending the original strand spaces. Then, we provide a term composition algorithm based on which new terms can be constructed. To ensure that security properties are maintained, we introduce the concept of term connections to express the existing connections between terms and encryption contexts. We illustrate the proposed composition process by using two existing protocols.Comment: 2008 IEEE International Conference on Automation, Quality and Testing, Robotics, Cluj-Napoca, Romania, May 2008, pp. 233-238, ISBN 978-1-4244-2576-

A UML-based static verification framework for security

Secure software engineering is a new research area that has been proposed to address security issues during the development of software systems. This new area of research advocates that security characteristics should be considered from the early stages of the software development life cycle and should not be added as another layer in the system on an ad-hoc basis after the system is built. In this paper, we describe a UML-based Static Verification Framework (USVF) to support the design and verification of secure software systems in early stages of the software development life-cycle taking into consideration security and general requirements of the software system. USVF performs static verification on UML models consisting of UML class and state machine diagrams extended by an action language. We present an operational semantics of UML models, define a property specification language designed to reason about temporal and general properties of UML state machines using the semantic domains of the former, and implement the model checking process by translating models and properties into Promela, the input language of the SPIN model checker. We show that the methodology can be applied to the verification of security properties by representing the main aspects of security, namely availability, integrity and confidentiality, in the USVF property specification language