Security use cases and modeling

What is a use case?

A use case is a sequence of actions that provide a measurable value to an actor. Another way to look at it is that a use case describes a way in which a real-world actor interacts with the system. An essential use-case is a simplified, abstract, generalized use case that captures the intentions of a user in a technology- and implementation-independent manner. An essential use case is a structured narrative, expressed in the language of the application domain and of users, comprising a simplified, generalized, abstract, technology-free and implementation-independent description of one task or interaction. An essential use case is complete, meaningful, and well designed from the point of view of users in some role or roles in relation to a system and that embodies the purpose or intentions underlying the interaction.