A multi-owner data sharing scheme efficiently supporting dynamic scenario on public clouds

A naive way for data privacy and security is encrypting data before outsourcing to the cloud. However, encryption triggers a new challenge in a fine-grained access control system, where there are many data owners and membership is dynamically changed. Existing schemes either solve security threats caused by dynamic membership with high cost, such as data re-encryption and/or key re-distribution, or only apply to single-owner scenarios in spite of eliminating the heavy burdens of data owner. This paper presents a multi-owner data sharing scheme with fine-grained access control, which achieves a high efficiency and supports the dynamic scenario. Benefiting from broadcast group key management and group signature techniques, the scheme allows any user to share data with others and it only takes constant time to deal with the change of membership, including user register, revocation and attributes change. Our scheme also achieves data owners' identity privacy preserving. Security analysis and extensive simulating experiments prove the high efficiency and security of proposed scheme.