A method for authenticating a first communication apparatus by a second communication apparatus and for opening a secure communication channel between the first and second communication apparatus in view of subsequent data exchanges between said first and second communication apparatus through said secure communication channel, the first apparatus comprising at least one storage medium suitable for storing at least: - an nth encryption certificate comprising a first public key associated with the first apparatus and a signature affixed by a certification authority that issued the encryption certificate, and - a first private key associated asymmetrically with the first public key, the nth encryption certificate being recognized by the second apparatus, the method comprising: - a first step of transmission from the first apparatus to the second apparatus of said nth encryption certificate, - a first step of verification by the second apparatus of the signature of said nth encryption certificate, - a first step of generation by the second apparatus of a first encryption key, the latter comprising at least one part of a challenge, - a first step of encryption by the second apparatus with said first public key of the first encryption key, - a second step of transmission from the second apparatus to the first apparatus of the first encrypted encryption key, - a first step of decryption by the first apparatus with said first private key of said first encrypted encryption key, - a second step of generation by the first apparatus of a response to the challenge, - a third step of transmission from the first apparatus to the second apparatus at least of the response to the challenge, and - a second step of verification by the second apparatus of the response to the challenge, and wherein said first encryption key is used to encrypt or decrypt said subsequent exchanges between the first communication apparatus and the second communication apparatus through the secure communication channel. - an nth encryption certificate comprising a first public key associated with the first apparatus and a signature affixed by a certification authority that issued the encryption certificate, and - a first private key associated asymmetrically with the first public key, the nth encryption certificate being recognized by the second apparatus, - a first step of transmission from the first apparatus to the second apparatus of said nth encryption certificate, - a first step of verification by the second apparatus of the signature of said nth encryption certificate, - a first step of generation by the second apparatus of a first encryption key, the latter comprising at least one part of a challenge, - a first step of encryption by the second apparatus with said first public key of the first encryption key, - a second step of transmission from the second apparatus to the first apparatus of the first encrypted encryption key, - a first step of decryption by the first apparatus with said first private key of said first encrypted encryption key, - a second step of generation by the first apparatus of a response to the challenge, - a third step of transmission from the first apparatus to the second apparatus at least of the response to the challenge, and - a second step of verification by the second apparatus of the response to the challenge,