Purpose Organisation

One of the principles of privacy management is making use of purposes for indicating why data is stored, and also why access to information is requested during the manipulation of the stored data. Many Privacy Enhancing Technologies (PETs) – such as the Hippocratic Database, Platform for Privacy Preferences (P3P), and Platform for Enterprise Privacy Preferences (EP3P) – make use of purposes as part of their basic operation. Little work has, however, been done on the proper organisation of purposes. Some of the work that has been done suggests that purposes can be placed in a hierarchy. This form of organisation is done to facilitate the logical grouping of purposes. Since purposes are critical to the operation of PETs – to ensure proper privacy management – they must be carefully examined so as to ensure that the way in which they are organised, adds more value to the act of organising and using than that of a logical grouping. This paper considers the organisation of purposes by arguing that they can be placed in a lattice, and that the use of such a purpose lattice offers improved protection of privacy. It does so by examining the already proposed idea of purpose hierarchies, and extending this idea by placing purposes in a lattice. It considers the representation of purposes in the lattice, the relationship between purposes in the lattice, and also how the relationships presented in a lattice can be used to accommodate a more flexible use of purposes for privacy management. The paper provides a foundation for future research of purpose organisation and management. Furthermore it introduces the concept of compound purposes, that is, purposes that are defined in terms of other purposes are presented. The use and implication of compound purposes are, however, not yet explored.