Cryptography for Privacy

Abstract

Abstract The increasing levels of data collection and processing, and the consequential risks to both individual users and society, have led to rising demands for privacy. This chapter first discuses different notions of privacy, including anonymity, and how cryptography relates to them. It then reviews a range of cryptographic privacy-enhancing technologies that can be used to support a variety of privacy objectives. The first is Tor, which is used to support anonymity on the internet. Next, it is shown how zero-knowledge proofs enable truths to be communicated without revealing unnecessary information. The goal of secure multiparty computation (MPC) is to enable sensitive data from multiple sources to be input to a computation while maintaining the privacy of the component data items. Finally, a range of further technologies are introduced, including blind signature schemes, group signature schemes, homomorphic encryption, private set intersection and private information retrieval.