FAME: Federated authority management for attribute-based encryption scheme in blockchain-assisted data marketing

Data marketing serves as a centralized third party, aggregating data owners and trading their data with buyers to promote data circulation. However, the security and privacy of marketing rely on a trusted central authority, single points of failure and rights abuse can easily cause untrusted marketing and data leakage. In this paper, we propose a federated authority management for an attribute-based encryption (ABE) scheme in blockchain-assisted data marketing. First, we design an authority blockchain with a threshold issuance protocol to replace the trusted authority in ABE, which achieves trusted authorization for marketing and eliminates the single points of failure. Second, we design an on/off-chain phased right revocation method, which efficiently revokes a buyer's access rights by invoking smart contracts to update the on-chain rights status, and without requiring off-chain re-authorization. Thus, this method prevents insecure marketing due to the abuse of rights. Theoretical analysis shows that our scheme could protect marketing security and data privacy. Experimental results confirm that it reduces the access and revocation cost to a constant level and decreases the storage overhead of marketing by n times compared to existing schemes.