A method includes acquiring a root certificate of a first node; generating a target sub-certificate based on the root certificate, where the target sub-certificate includes a first sub-certificate of a first functional module of a first application associated with the first node; and sending the target sub-certificate to a terminal device. The target sub-certificate is used for the first functional module of the first application in the terminal device communicating through the target sub-certificate. In such a manner, a capability of managing the first sub-certificate of the first functional module in the terminal device can be improved.