Selective Owner-Side Encryption in Digital Data Markets: Strategies for Key Derivation

The combined adoption of selective encryption and smart contracts deployed on blockchains allows data owners to maintain control over their data when traded on digital data market platforms. Selective encryption, combined with key derivation techniques, guarantees that only customers who are entitled to access a resource can read its content. The adoption of smart contracts deployed on a blockchain permits to regulate the interplay among parties, the possible economic incentives to be paid to the owners, and the exchange of the information necessary for resource decryption (i.e., updates to the key derivation structure) upon payment. However, operations on blockchains have a cost. In this paper, we propose two approaches for updating the key derivation structure to enable customers to access resources, while limiting access times to resources and the cost of write operations on the blockchain to enforce purchases.