Disclosed herein are methods, systems, and apparatus, including computer programs encoded on computer storage media, for document registration. One of the methods includes: at a service platform, receiving first information related to an order, wherein the first information is provided, or to be provided, to a service authority for clearance of the order; at the service platform, encrypting at least a portion of the first information to generate encrypted first data; and sending the encrypted first data to a blockchain network to store the encrypted first data on a blockchain managed by the blockchain network, wherein the encrypted first data are stored on the blockchain through consensus of blockchain nodes of the blockchain network.