Research on key techniques of cryptographic access control and properties optimisation in cloud storage

With the analysis of data privacy protection requirement from the users, we proposed cryptographic access control scheme and key distribution scheme based on ciphertext-policy attribute-based encryption (CP-ABE), and gave a hierarchy based on CP-ABE key generation algorithm. This scheme uses precise identity and hierarchal structure as the user attributes, and supports hierarchal key generation. As the cloud data are encrypted by the users, the data privacy protection can be effectively achieved in cloud storage against network attackers even if cloud service provider (CSP), suitable for the multi-user who has hierarchal structure attributes sharing cloud storage services environment. We also proposed two schemes for improving the usability of cloud storage system. The first one is that the metadata information of unstructured data are stored in cloud using non-relational database MongoDB, which can greatly improve the speed of data access. The second is data migration algorithm based on physical volume, which can migrate data to the matching devices automatically depending on user access frequency value. Experimental results showed that these programs were able to improve the storage efficiency of cloud storage system. The study is of theoretical significance and practical value to the similar systems.