Abstract: A method for verifying the security of a message (Msg) transmitted and received in electronic form comprises on the transmitting side the steps of associating with the message a univocal message identifier (IDMsg) and a message owner identity checking identifier (IDCR) which is obtained by applying to the univocal message identifier (IDMsg) an encoding (12) associated with the owner of the message to be transmitted. On the receiving side the method comprises the steps of verification and signaling of the fact of having or not having already received a message with the same univocal message identifier (IDMsg) associated and ascertaining agreement between the univocal message identifier (IDMsg) associated with the received message and the result (IDDCR) of a decoding of the checking usemame (IDCR). A verification system and device in accordance with the method are also discussed.