Patent ID: 7324645

Claim:
A method to authenticate a mobile station in a mobile network comprising: authenticating the mobile station with user-to-user data exchange; exchanging authentication data during call set-up or during a call; wherein an encryption key is agreed between two mobile stations and the mobile stations execute a mutual authentication and key agreement protocol based on public-key cryptography and, wherein a second mobile station is authenticated by: a first mobile station constructing and sending to the second mobile station a first message, the second mobile station receiving the first message, constructing and sending a second message to the first mobile station, the first mobile station receiving the second message, checking the validity of the information in the second message, if the information is verified valid the first mobile station accepting to share a shared encryption key K with the second mobile station, the first mobile station constructing and sending a third message to the second mobile station, the second mobile station receiving the third message and verifying the validity of the information, if the information is valid the second mobile station accepting the sharing of the shared encryption key K with the first mobile station.