Abstract: In an encryption communication system, an encrypt key ID of an encrypt apparatus appearing on a communication path between terminals is acquired by using a key seek packet, and an encrypt key ID is automatically learned based upon a key seek response packet for notifying the acquired encrypt key ID. As a result, communication data between the terminals are encrypted/decrypted, transparently relayed, and discarded by the respective encrypt apparatuses. Even when a communication network is made large and complex, the network for the encrypt communication can be readily managed.

Abstract: A protocol processing apparatus is presented having a plurality of CPUs for processing communication protocol data in parallel so as to achieve a high measure of efficiency. The apparatus provides a common memory including a CPU state table that is accessible by the plurality of CPUs. The CPU state table associates an idle flag, a remote node identifier, and a process start time with each of the plurality of CPUs. At least one line interface selects a CPU from the plurality of CPUs according to the contents of the CPU state table, selecting an idle CPU if one is available, selecting a CPU with the oldest process start time if no idle CPU is available, or selecting a busy CPU if the communication data to be processed is related to communication data already running on the busy CPU.