A query request is forwarded to a plurality of service provider servers by a proxy server that determines a serial number based on the query request. An encrypted query result corresponding to the query request is received from each service provider server, and a copy of the encrypted query result is stored as a result to be audited in a blockchain that associated with each service provider server. An audit request is sent to at least one service provider server. The result to be audited is obtained from the blockchain corresponding to the service provider server. As a standard result, an encrypted query result is received from the service provider server. As an audit, the standard result received from the service provider server is compared with the result to be audited that obtained from the blockchain that associated with the service provider server.