Computer-implemented cryptographic method for improving a computer network, and terminal, system and computer-readable medium for the same

A method of increasing operational efficiency of one or more computers or controllers at a terminal in a multiple-node digital communications network, comprising:

• generating at least one symmetric first key(s), across all participating nodes in the multiple-node digital communications network;
• securely distributing the at least one first key(s) in encrypted form to multiple participating nodes of the multiple-node digital communications network, using at least one asymmetrically established second key(s), the participating nodes including at least one message-transmitting node(s) and at least one message-receiving node(s);
• generating at least one symmetric third key(s) for one or more communication session that includes one or more communications from the at least one message-transmitting node(s) to the message-receiving node(s);
• encrypting at least one payload message using the at least one third key(s) at the at least one message-transmitting node(s), sending the encrypted at least one payload message, and receiving the encrypted at least one payload message at the at least one message-receiving node(s);
• encrypting the at least one third key(s) using the at least one first key(s), sending the encrypted at least one third key(s), and receiving the encrypted at least one third key(s) at the at least one message-receiving node(s);
• decrypting the at least one third key(s) using the securely distributed at least one first key(s), at the at least one message-receiving node(s);
• decrypting the at least one encrypted payload message using the decrypted at least one third key(s), at the at least one message-receiving node(s);
• wherein the network is a motor vehicle network entirely internal to one or more motor vehicles and comprises one or more of a secure application layer and a secure link layer, which secures the motor vehicle network.