A layered architecture for privacy - enhancing technologies

While a number of privacy-enhancing technologies have been proposed over the past quarter century, very little has been done to generalise the notion. Privacy-enhancing technologies have typically been discussed for specific applications (such as confidential and/or anonymous e-mail) or in specific contexts (such as on the Internet). This paper takes cognisance of existing privacy-enhancing technologies, abstracts from them to a more general environment, and structures the technologies in a general architecture, based on the relationships between the technologies. The resulting architecture consists of four layers, viz the personal communications, identity management, organisational safeguards and personal control layers. It is also argued that a strong ordering exists between the layers — in the order