An authentication method, an authentication apparatus, and an authentication system for the communications field are described. The authentication includes receiving, by a communications network element, a request from a user equipment (UE) comprising a first identifier that is an international mobile subscriber identity (IMSI). The communication network element, in response to the request, sends the first identifier to a home subscriber server. The communications network element, upon authenticating the UE successfully, sends a second identifier to a key management center (KMS) to facilitate the KMS generating a subscriber private key corresponding to the second identifier and sending the subscriber private key to the communications network element. The communications network element thereafter sends the subscriber private key to the UE.