As a software system evolves, security concerns need to be analyzed to re-evaluate the impact of changes on the system and the assumptions on environmental properties. Traditionally, the security requirements were handled in an ad-hoc way, while requirement models are often embedded in natural language descriptions which lead to inconsistent interpretations with respect to the meaning of the requirements. These made it difficult to analyze for requirements changes. By adopting a model-based engineering methodology, we propose to investigate such changes using a consistent conceptual model of evolving security requirements which incorporates the state-of-art requirement modeling languages such as Tropos and Problem Frames. To address the challenge of evolutionary security requirements, we lay out the conceptual meta-models, and the general methodology to handle changes on security requirements, including how to represent security requirements, how to model the changes of them, how to manage the changes and how to argue that the changes are fit for the purposes.
Read on in the D.3.2 Methodology for Evolutionary Requirements deliverable.