An example operation may include one or more of receiving a request for access to data of a user, the request comprising an identification of a requestor and an identification of the data, determining, via a cognitive engine, whether or not to provide access to the data of the user based on context associated with the user, in response to determining to provide access to the data of the user, invoking chaincode which retrieves access to the data of the user from a blockchain and provides the requestor with access to the data of the user, and storing a result of the determination by the cognitive engine via the blockchain.