Practical privacy-enhancing technologies

The purpose of this paper is to provide an overview of current cryptographic Privacy-Enhancing Technologies (PETs) and show practical examples of services where these technologies can be deployed. In particular, the paper covers anonymous routing protocols, privacy-enhanced authentication systems and general-purpose systems like group signatures. Besides the overview of existing cryptographic technologies and relevant use-case scenarios, we provide also practical information regarding the performance of PETs on resource-restricted devices such as smart-cards, smart-phones and microcontrollers.