Fine-grained searchable encryption over encrypted data in multi-clouds

Cloud computing has increased rapidly due to its abundant benefits in terms of low cost and accessability of data. Privacy protection and data security are two issues in cloud computing, as users often outsource sensitive information to honest-but-curious cloud storage providers (CSP).While encryption seriously obsoletes the traditional information retrieval over plaintext. Therefore, searchable encryption (SE) technology which allows the users to securely search over ciphertext through keywords and selectively retrieve files of interest becomes important. Dealing with single CSP is predicted to become less popular with cloud customers for fear of risks of single-point failure threat and potential malicious insiders. To tackle above problems, two schemes based on Identity-Based Encryption (IBE) and Key-Policy Attribute- Based Encryption (KP-ABE) are proposed in multi-clouds environment, respectively. Through rigorous security and performance analysis, both schemes can ensure security and reliability, and greatly reduce computational burden.