CSCAC: One constant-size CPABE access control scheme in trusted execution environment

The popularity of versatile mobile devices has been increasing concerns about their security. How to protect the sensitive data is an urgent issue to be solved. Ciphertext-policy attribute-based encryption (CPABE) is a practical method for encrypting data and can utilise user's attributes to encrypt the sensitive data. In this paper, we propose a constant-size CPABE access control (CSCAC) model by using the Trusted Execution Environment to manage the dynamic key generated by attributes. The original data is encrypted by a symmetric storage key, then the storage key is encrypted under an AND-gate access policy. Only the user who possesses a set of attributes that satisfy the access policy can recover the storage key. The security analysis shows the design of this access control scheme reduces the burden and risk in the case of one single authority.