Patent attributes
This specification describes techniques for processing service requests. An electronic credential request including a user identifier is received from a client. An electronic credential that corresponds to the user identifier and a user public key that corresponds to the user are retrieved. A hash operation is performed on the user public key and the electronic credential by using a hash algorithm to obtain a hash value that is signed within a predetermined time period. Server signature information is generated using the hashed credential, and transmitted with the electronic credential to the client. The server signature information is cryptographically verifiable by the client and enables the client to generate a two-dimensional barcode based on the electronic credential.
