The API is called by the method authorized to APP. Each APP contains the AK and SK information. The information is used for signature verification at the API request. We can create the APP in the application management page of the gateway console. The corresponding AK and SK information is allocated to each APP after it is created. You should carry the signature information at the request. The gateway makes the identity verification for you by the signature information. If the AK and SK information is lost, SK may be reset in the console to prevent the API from being called by others.