Encryption communication system, encryption communication apparatus, and encryption communication method

An encryption communication system comprising:

• a first communication device and a second communication device each including a first quantum key delivery device and a second quantum key delivery device, the first communication device and the second communication device being coupled to each other by the first quantum key delivery device;
• and
• a third communication device that includes two of the second quantum key delivery devices, is coupled to the first communication device by one of the second quantum key delivery devices, and is coupled to the second communication device by the other of the second quantum key delivery devices,
• wherein the third communication device including a random number key generation unit configured to generate a random number key for decrypting encrypted data by using data acquired from the first communication device and the second communication device by the two second quantum key delivery devices.

An encryption communication apparatus comprising:

• a data reception unit configured to receive data from a first network;
• a first quantum encryption communication unit configured to execute quantum encryption communication with a first node of a second network;
• a second quantum encryption communication unit configured to execute quantum encryption communication with a second node of the second network;
• a random number key generation unit configured to generate a random number key for decrypting encrypted data by using first data acquired by the first quantum encryption communication unit and second data acquired by the second quantum encryption communication unit;
• and
• a decryption unit configured to decrypt encryption data received by the data reception unit by using the random number key generated by the random number key generation unit.

An encryption communication method comprising:

• coupling a first communication device and a second communication device each having a first quantum key delivery device and a second quantum key delivery device to each other by the first quantum key delivery device;
• coupling a third communication device having two of the second quantum key delivery devices to the first communication device by one of the second quantum key delivery devices and to the second communication device by the other of the second quantum key delivery devices;
• and
• generating, by the third communication device, a random number key for decrypting encrypted data by using data acquired from the first communication device and the second communication device by the two second quantum key delivery devices.