A method for communicating between two communicating entities, a first communicating entity generating a data message comprising a payload and an authentication header (TOKEN), said method including: ▪ generating a message identifier (MES_ID) from a given parameter and from a date and inserting the identifier in an authentication header (TOKEN); ▪ inserting a plurality of authentication data comprising at least a user identifier (USER_ID) and an equipment identifier (EQ_ID) in the authentication header (TOKEN); ▪ determining and inserting a security profile (PRO_SEC) in the authentication header (TOKEN) defining the conditions of: ∘ encrypting the payload of the message issued by the first communicating entity; ∘ generating a data signature of the message and of the format of said generated signature; ▪ inserting the payload in the message to be transmitted, the second communicating entity (SERV) upon receipt of a message from the first communicating entity (CLIENT) decoding the authentication header (TOKEN) so as to: ▪ control the message identifier (MES_ID) to determine if the message has been issued within a predefined lapse of time; ▪ control the user's identifier (USER_ID) and the equipment identifier (EQ_ID) by comparing the value of these parameters with data stored in a memory of the second communicating entity (SERV) to determine if the equipment or the user has been suspended or revoked; ▪ control the encrypting parameter (P1, P3) of the security profile (PRO_SEC) of the received message to decrypt when necessary the payload with the private key of the second communicating entity (SERV); ▪ control, when necessary, the signature parameter (P2, P4) of the security profile (PRO_SEC) of the received message to verify when necessary the signature by means of the public key (KApub) of the first communicating entity (CLIENT). ▪ generating a message identifier (MES_ID) from a given parameter and from a date and inserting the identifier in an authentication header (TOKEN); ▪ inserting a plurality of authentication data comprising at least a user identifier (USER_ID) and an equipment identifier (EQ_ID) in the authentication header (TOKEN); ▪ determining and inserting a security profile (PRO_SEC) in the authentication header (TOKEN) defining the conditions of: ∘ encrypting the payload of the message issued by the first communicating entity; ∘ generating a data signature of the message and of the format of said generated signature; ∘ encrypting the payload of the message issued by the first communicating entity; ∘ generating a data signature of the message and of the format of said generated signature; ▪ inserting the payload in the message to be transmitted, ▪ control the message identifier (MES_ID) to determine if the message has been issued within a predefined lapse of time; ▪ control the user's identifier (USER_ID) and the equipment identifier (EQ_ID) by comparing the value of these parameters with data stored in a memory of the second communicating entity (SERV) to determine if the equipment or the user has been suspended or revoked; ▪ control the encrypting parameter (P1, P3) of the security profile (PRO_SEC) of the received message to decrypt when necessary the payload with the private key of the second communicating entity (SERV); ▪ control, when necessary, the signature parameter (P2, P4) of the security profile (PRO_SEC) of the received message to verify when necessary the signature by means of the public key (KApub) of the first communicating entity (CLIENT). <EOS>