A bus-based communication system, may include a communication bus connecting a plurality of nodes. A first node, of the plurality of nodes, may receive a first message on the communication bus, the first message having been broadcast on the communication bus by a second node of the plurality of nodes. The first message may include a modular exponentiation associated with a private key of the second node. The first node may compute a shared secret key, associated with the plurality of nodes, based at least in part on the modular exponentiation and a private key of the first node.