Privacy-Preserving Social Search: Primitives and Realisation

To mitigate the data breach issue in online social networks, this thesis builds an encrypted search system. The system can process queries on the encrypted data, and it can be used to support real-world social network services. To further improve the security of the system, this thesis reviews the underlying cryptographic primitives used by the system and propose a new cryptographic primitive to address an attack with a moderate cost.