When implementing an ID document, most of us agree that making it secure is an important - if not the most important - objective. It is, however, difficult to agree on what this really means. There are many aspects to document security and all too often one or more of the most important aspects are overlooked. Comprehensive identity solutions require us to consider the critical success factors for the entire identity solution life cycle. We need better tools to help us deal with this daunting task. One such tool is a formal methodology that encompasses the problem domains, technology options, security needs and solutions development practices that allow us to address real business problems. The methodology can be viewed in the context of a Document Security Model (DSM), something analogous to the Information Technology (IT) identity management methodologies in use today. As Jeff Setrin explains, modelling is a powerful concept that offers many potential benefits, including the ability to leverage the experience of those who face similar problems.