Abstract
This paper presents the CORAS method for model-based security analysis. The presentation is case-driven. We follow two analysts in their interaction with an organisation by which they have been hired to carry out a security risk analysis. The analysis is divided into seven main steps, and the paper devotes a separate section to each of them. The paper focuses in particular on the use of the CORAS security risk modelling language as a means for communication and interaction during the seven steps.