An authentication method, an authentication apparatus, and an authentication system for the communications field are described. The authentication includes sending, by first user equipment, a first random parameter to second user equipment. The second user equipment obtains a first user identifier, a second user identifier, and a second random parameter; and generates a second authentication feature based on the first user identifier, the second user identifier, the first random parameter, and the second random parameter. The second user equipment sends the second authentication feature to the first user equipment for authentication. The first user equipment, after authentication, generates a first authentication feature. The first authentication feature is sent to the second user equipment for authentication.