Data transmission method, communication processing method, device, and communication processing program

A data communication method according to one aspect of this disclosure comprises a step (S118) in which a first device (100-1) encrypts a packet, addressed to a second device (100-2), by using a first associated cryptographic key (172) to generate a first encrypted packet (24); the steps (S120 to S128) in which the first device (100-1) determines a device to which the first encrypted packet should be transmitted, encrypts the first encrypted packet using a second associated cryptographic key to generate a second encrypted packet, and transmits the second encrypted packet to the determined device; and the steps (S200 to S218) in which a local device judges whether the first encrypted packet, as decrypted, is addressed to the local device or not, and, if not, then executes the steps of determining another device and transmitting the packet to that other device, and, if so, then further decrypts the first encrypted packet. (Automatic translation with Google Translate, no legal value)