ENCRYPTION COMMUNICATION SYSTEM AND METHOD FOR DELIVERING ENCODING KEY

摘要

PROBLEM TO BE SOLVED: To alleviate a load on a network at delivery responding of an encoding key used for an encryption communication group. SOLUTION: A group encryption key managing unit 1 generates a group key, and transmits the key to terminal units T2 to T6 belonging to a communication group 13 via a router 5 and a router 8. The terminal units T2 to T6 transmit delivery response data D3 for transmitting reception of the group key to the router 5. The router 5 transmits the data as a simultaneous response data D4 to the unit 1 based on the data D3. The units T5 and T6 transmit the data D3 for transmitting the reception of the key to the router 8. The router 8 transmits the data D3 to the unit 1 as the data D4 based on the data D3.