The Secret Lives of Assumptions: Developing and Refining Assumption Personas for Secure System Design

Personas are useful for obtaining an empirically grounded understanding of a secure system's user population, its contexts of use, and possible vulnerabilities and threats endangering it. Often, however, personas need to be partly derived from assumptions; these may be embedded in a variety of different representations. Assumption Personas have been proposed as boundary objects for articulating assumptions about a user population, but no methods or tools currently exist for developing and refining these within the context of secure and usable design. This paper presents an approach for developing and refining assumption personas before and during the design of secure systems. We present a model for structuring the contribution of assumptions to assumption personas, together with a process for developing assumption personas founded on this model. We also present some preliminary results based on an application of this approach in a recent case study

A Framework for Constructive Design Rationale

This paper proposes a framework for describing design rationale as a constructive notion rather than a fixed record of design reasoning. The framework is based on two views: an instance-based view of design rationale as an ordered set of decisions, and a state-space view of design rationale as a space of solution alternatives. The two views are connected with each other using the function-behaviour-structure (FBS) ontology. Constructive design rationale is defined and categorised based on reformulations of the function, behaviour or structure of the rationale. The drivers of the different reformulations are represented in the situated FBS framework