Method for authentication between a portable telecommunication object and a public access terminal

Abstract

A method of mutually authenticating, firstly, a portable object () assigned a unique identifier (MSISDN) and including first wireless communications means and, secondly, a public access terminal () including second wireless communications means and telecommunications means for communicating via a telecommunications network (). The portable object () is assigned a wireless communication key (Kme). An authentication server () is installed on the network () and adapted to determine the key Kme from the identifier (MSISDN). The identifier (MSISDN) of the portable object () is sent to the terminal () and then from the terminal () to the authentication server (). The authentication server () determines the key Kme and allocates the wireless communication key Kme to a calculation unit (). The calculation unit () calculates a session key (Ksession) from the key Kme of the portable object () and allocates the key Ksession to the public access terminal (). The terminal () sends the portable object () a first message signed using the key Ksession, the portable object () acquires the key Ksession from the first message and the key Kme, and authenticates the terminal () by verifying the signature of the first signed message. The portable object () sends the terminal () a second message signed with the key Ksession, and the terminal () authenticates the portable object () by verifying the signature of the second signed message.