using at least one network consisting of at least one node , a multi - hop communication system is formed in which data are received and forwarded from a transmitting first node to a second node receiving the data via at least one third node interposed between the first and the second node . for transmission , the data are subdivided into packets that have a useful data portion and at least one first control data portion associated with the multi - hop method and a second control data portion associated with the network . the data are encrypted using a first public key determined by the first node and the second node , but only the useful data portion is encrypted using the first public key .