A method and device device for authentication are provided. The method includes: a second authenticator transmitting to a first authenticator a first identity authentication message; the first authenticator transmitting to an authentication server a second identity authentication message; the authentication server verifying the validity of a secure domain where the second authenticator is at and of the first authenticator on the basis of the second identity authentication message; the authentication server returning to the first authenticator a third identity authentication message; the first authenticator transmitting to the second authenticator a fourth identity authentication message; the second authenticator proceeding to verification when the fourth identity authentication message is received; the second authenticator transmitting to the first authenticator a fifth identity authentication message; and the first authenticator proceeding when the fifth identity authentication message is received.