The embodiments of the present disclosure disclose an authentication method, a system, a server, and a user node are disclosed herein. The method includes: generating, by a server, a server session key according to the identity information, at least one login information parameter, and the validity period included in the login information, generating at least one session key parameter of a user node according to the generator point of the algebraic curve, and sending at least one session key parameter of the user node to the user node; generating, by the user node, a user node session key according to at least one session key parameter of the user node; performing, by the server and the user node, mutual authentication according to the session keys. The authentication solution under the present disclosure is simple and practicable, and is also applicable to authenticating the user node in a grid computing platform.