Communication system, key management server device, router, and computer program product

A communication system comprising:

• a plurality of key management server devices each comprising a first processor;
• and
• a router comprising a memory and a second processor coupled to the memory,
• the first processor of one of the plurality of key management server devices being configured to:
• share a bit string with another facing key management server device by quantum key distribution;
• encrypt a decryption key by using the shared bit string and transmit a control signal including the encrypted decryption key and key identification information identifying the decryption key to the facing key management server device;
• and
• supply the decryption key to the router upon receiving the control signal without waiting for a request to generate the decryption key from the router when the one key management server device is connected to the router, and
• the second processor being configured to:
• receive a packet encrypted with an encryption key corresponding to the decryption key identified by the key identification information;
• and
• decrypt the packet by using the decryption key supplied from the one key management server device without requesting the one key management server device to generate the decryption key.

A key management server device comprising:

• a memory;
• and
• a processor coupled to the memory and configured to:
• share a bit string by quantum key distribution;
• receive a control signal including key identification information and a key length, the key identification information identifying an encryption key generated from the bit string, and the key length indicating a length of the encryption key;
• and
• generate a decryption key corresponding to the encryption key from the bit string based on the key identification information and the key length, upon receiving the control signal without waiting for a request to generate the decryption key from a router.

A router comprising:

• a memory;
• and
• a processor coupled to the memory and configured to:
• receive a packet encrypted with an encryption key;
• and
• decrypt the packet by using a decryption key supplied from a key management server device without requesting the key management server device to generate the decryption key.

A computer program product comprising a non-transitory computer-readable medium including programmed instructions, the instructions causing a computer to execute:

• sharing a bit string by quantum key distribution;
• receiving a control signal including key identification information and a key length, the key identification information identifying an encryption key generated from the bit string, and the key length indicating a length of the encryption key;
• and
• generating a decryption key corresponding to the encryption key from the bit string based on the key identification information and the key length, upon receiving the control signal without waiting for a request to generate the decryption key from a router.