In a method and system for securely transferring a message (N) from a transmitter unit (SE) to a receiver unit (EE), a message sent by a transmitter unit (SE) is thereby transmitted to a receiving antenna array (EAA) comprising a plurality of receiving nodes (EK). The receiving nodes (EK) of the receiving antenna array (EAA) each verify the received message as originating from an authorized transmitter unit (SE) before the verified message is forwarded by each receiving node (EK) to the receiving unit (EE). The method and system effectively protects the message transmission from the introduction of undesired data by an attacker, and by an attack wherein the lifespan or operating time of the partially battery-powered nodes is reduced by increased current consumption.