The emergence of cloud computing brings a paradigm shift to the way that data is stored, accessed and utilized. Especially, outsourcing data to the public cloud enjoys unlimited resources with great economic savings for both data owners and users. However, user privacy concerns have been a major hurdle for the widespread adoption of the public cloud technology. Encryption techniques can protect the confidentiality of users' data, however, supporting effective data utilization such as search operations over encrypted data become a key challenge. Existing techniques are either too computationally expensive, or lack enough flexibility to be adopted by cloud users in practice. This project aims at protecting user privacy in the cloud. It develops the tools to provide privacy-assured, usable, and efficient data utilization services in outsourced cloud storage systems. Specifically, it tackles the above challenges by combining cryptography with information-retrieval techniques, and focuses on three aspects: (1) the design of novel keyword search schemes over encrypted data with rich functionalities, including ranked search and multi-keyword search; (2) the design of privacy-preserving search schemes over data that are represented using various structures, such as graphs; (3) new approaches for protecting user privacy in the mobile cloud setting. This research also includes a prototyping and experimentation plan. Ensuring user privacy is fundamental to the success of public cloud deployment. This project also develops curricula and teaches and supervises students. Materials of this project will be made available online as tutorials, software packages, and publications of general interest.
