Subscriber authentication

The invention claims an is provided at the user authentication in a telecommunications system and method, and method comprises the steps: The retrieval and key of the user; twoThe extendable line for searching of the authentication; andThe parameter of the is composed characterised, retrieves of the operating of user; twoThe first one-way function, according to the key and parameter is equal to the first intervals; By the second one-way function, according to the searching and first password computation, outputIs arranged in the output by the withdraw authentication response; And and authentication to respond the user authentication.