Traceable CP-ABE for Outsourced Big Data in Cloud Storage

Ciphertext Policy Attribute Based Encryption (CP-ABE) is a promising cryptographic solution for the unauthorized access to the outsourced big data in the cloud environment. However, most of the existing CP-ABE schemes do not have the provision to trace the users who misuse their secret key for profit intention which indeed reduces the CP-ABE schemes security. Thus, in this paper, we propose traceable CP-ABE (T-CP-ABE) for outsourced big data in cloud storage. Our scheme has the provision to dynamically trace who is decrypting the ciphertext during outsourced proxy decryption, which helps to identify the malicious users who misuse their secret key for profit intention. Furthermore, our scheme has an efficient key sanity check, which ensures that only the well-formed secret key is used for decryption. Security analysis proves that our scheme resist against the secret key forging and chosen-plaintext attacks. Performance evaluation proves that our T-CP-ABE scheme is efficient than other traceability schemes.