P2U: A Privacy Policy Specification Language for Secondary Data Sharing and Usage

Within the last decade, there are growing economic social incentives and opportunities for secondary use of data in many sectors, and strong market forces currently drive the active development of systems that aggregate user data gathered by many sources. This secondary use of data poses privacy threats due to unwanted use of data for the wrong purposes such as discriminating the user for employment, loan and insurance. Traditional privacy policy languages such as the Platform for Privacy Preferences (P3P) are inadequate since they were designed long before many of these technologies were invented and basically focus on enabling user-awareness and control during primary data collection (e.g. by a website). However, with the advent of Web 2.0 and Social Networking Sites, the landscape of privacy is shifting from limiting collection of data by websites to ensuring ethical use of the data after initial collection. To meet the current challenges of privacy protection in secondary context, we propose a privacy policy language, Purpose-to-Use (P2U), aimed at enforcing privacy while enabling secondary user information sharing across applications, devices, and services on the Web.