A Pattern Collection for Privacy Enhancing Technology Cornelia Graf 1 , Peter Wolkerstorfer 1 , Arjan Geven 1 , Manfred Tscheligi 1,2 (1) CURE Center for Usability Research & Engineering Modecenterstraße 17 / 2 1110 Vienna +43.1.743 54 51 {last name}@cure.at (2) ICT&S Center University of Salzburg Sigmund-Haffner Gasse 18 5020 Salzburg +43.662.8044.4811 manfred.tscheligi@sbg.ac.at Abstract— Patterns are a useful approach to describe, organize and present solutions and best practices for design problems. Although much work can be found concerning either patterns or privacy, work focusing on patterns for Privacy Enhancing Technologies (PET) is very rare. This paper describes the development of User Interfaces Patterns for PET and the benefit of using them. We used different proven approaches and guidelines and merged them for creating efficient and useable patterns for PETs. Anyhow, some of our patterns were not tested much with end-users, so further tests will be necessary to prove worth of the patterns. Nevertheless we maintain that our patterns will support the development of PET UIs. In this paper, we provide a short overview of the whole pattern collection and present two patterns in detail. Keywords- patterns; privacy; user interfaces desing; privacy enhancing technologies; pattern development; pattern approach. I. INTRODUCTION Patterns provide solutions that have been successfully used for many years for specific problems. This paper describes the development of patterns for different User Interfaces (UI) for PETs and presents two of them more detailed. In current literature, patterns for PETs are very rare; approaches concerning patterns for privacy enhancing technologies are presented by [6], [10], [15], [16], [17] and [18]. The usage of PETs for privacy protection is a very important aspect for users’ online life. Therefore, the lack of patterns concerning UIs for PETs is a big deficiency, for developers and designers as well as end-users. To help designers and programmers when dealing with the creation of UIs for privacy enhancing technologies we developed twelve patterns for PETs. In the following Section, we will give an overview about the current research in the field of privacy patterns. Section III presents the development of our patterns approach and gives an overview of the PET patterns. In Section IV, we describe two of them in detail. In the last Section, we will discuss our approaches and give an overview about our future research. II. RELATED WORK In literature, much work can be found concerning either privacy or patterns but our literature research showed a lack of work concerning patterns for PETs. Goldberg [3], [4] and Goldberg et al. [5] presented an overview about currently existing privacy enhancing technologies and gave an outlook of future PETs. Schumacher [17] presented two patterns, one deals with protection against cookies and the other one with pseudonymous mailing. Schümmer [18] pointed out another privacy pattern approach, which covers the filtering of personal information in collaborative systems. These patterns address how to protect personal data from transmission to others and how to filter information received from others. Other research concentrated on privacy protection and anonymity. Hafiz [6] presented a collection of privacy design patterns, which addresses anonymity solutions for various domains. Romanosky [15] developed three patterns, which describe how users can protect their privacy in web-based activities. Another topic concerns patterns, which are related to privacy policies. Sadicoff [16] introduced a pattern especially for affording user awareness for privacy policies of network sites. The approach of Lobato [10] dealt with the development of user-friendly privacy policies. In this paper, we present some patterns we created to support designers and developers when working on the development of UIs for PETs. III. PET PATTERNS Since the observing of privacy should be one main goal in users’ online behavior, it is necessary to provide PETs for supporting them. Our current work deals with the development of different user interfaces for privacy enhancing technologies. As patterns provide useful and proven approaches for design problems we decided to use them for the development of our PET UIs. However, while we looked for patterns and proven approaches we concluded that only few patterns for privacy enhancing technologies are available and that they were not adaptive for our requirements. Hence, we decided to work not only on UIs for PETs but furthermore on development of patterns for assisting future PET developers. The main requirement was to develop PET-UIs, which present the complex techniques of PETs in an understandable way to end-users. Another important requirement was to support users to protect their privacy in an active way. To achieve this we worked on solutions to 72 PATTERNS 2010 : The Second International Conferences on Pervasive Patterns and Applications Copyright (c) IARIA, 2010 ISBN: 978-1-61208-111-3