Abstract: An authentication method between a client (2) and a server (4) sharing a secret (6) includes the following steps: the server (4) generates at least one random value (40); the server (4) computes a first encrypted value (46); the server (4) concatenates the random value (40) and the first encrypted value (46) to form a challenge (10); the client (2) extracts the random value (40) and the first encrypted value (46) from the challenge (10); the client (2) computes a second encrypted value (48); the client (2) compares the first (46) and second (48) encrypted values; and the server (4) is authenticated by the client (2) if the first (46) and second (48) encrypted values match.

Abstract: A method is provided for authenticating a client terminal with an authentication server. The client terminal holds an authentication certificate. The method includes the following phases: obtaining at least once encryption parameter by the client terminal; encrypting the authentication certificate by the client terminal, based on the at least one encryption parameter, delivering an encrypted authentication certificate; transmitting the encrypted authentication certificate to the server, obtaining the at least one encryption parameter by the server; obtaining the at east one encryption parameter by the server; decrypting the encrypted authentication certificate, based on the at least one encrypting parameter, authenticating and delivering an authentication assertion if the authentication is positive.