Abstract
Cloud storage services enable users to remotely store their data and eliminate excessive local installation of software and hardware. There is an increasing trend of outsourcing enterprise data to the cloud for efficient data storage and management. However, this introduces many new challenges toward data security. One critical issue is how to enable a secure data collaboration service including data access and update in cloud computing. A data collaboration service is to support the availability and consistency of the shared data among multi-users. In this paper, we propose a secure, efficient and scalable data collaboration scheme SECO. In SECO, we employ a multi-level hierarchical identity based encryption (HIBE) to guarantee data confidentiality against untrusted cloud. This paper is the first attempt to explore secure cloud data collaboration services that precludes information leakage and enables a one-to-many encryption paradigm, data writing operation and fine-grained access control simultaneously. Security analysis indicates that the SECO is semantically secure against adaptive chosen ciphertext attacks (IND-ID-CCA) in the random oracle model, and enforces fine-grained access control, collusion resistance and backward secrecy. Extensive performance analysis and experimental results show that SECO is highly efficient and has only low overhead on computation, communication and storage.