Research on Timed Access of Sensitive Data Based on Dual Encryption

A timed access solution of sensitive data based on dual encryption scheme is proposed to solve the problem of timed deletion of shared sensitive data stored in outsourcing storage. In our solution, the shared sensitive data file is encrypted by symmetric encryption, and the encrypted file is randomly divided to form the extracted cipher component and the encapsulated cipher component. Then, the attribute based timed encryption algorithm is used to encrypt the symmetric key and extracted cipher component, which can generate access control object. Finally, the encapsulated cipher component is combined with the access control object and sent into the cloud server. By this scheme, the authorized user can decrypt the access control object in the time limitation, obtain the symmetric key and extract cipher component, compose the original ciphertext, and recover the plaintext. Once access windows period expire, any users are unable to decrypt the access control object, get the symmetric key, recover the plaintext, so as to realize the timed destruction of sensitive data. The security of the scheme is analyzed and proved by the adversary attack model.