Communication apparatus, communication method, communication system, and computer program

A communication apparatus comprising:

• a first communication unit that performs communication with a transmitting apparatus becoming a transmission origin of data by a first network;
• a second communication unit that performs communication with a receiving apparatus becoming a transmission destination of data by a second network;
• and
• a round trip time information acquiring unit that acquires round trip time information regarding a round trip time RTTL with the receiving apparatus on the second network and transmits the round trip time information to the transmitting apparatus.

A communication method comprising:

• a first round trip time information acquiring step of acquiring first round trip time information regarding a first round trip time RTTL between a receiving apparatus becoming a transmission destination of data and a relay apparatus performing relay with the receiving apparatus;
• an authentication and key exchanging step of performing authentication and key exchange with the receiving apparatus through the relay apparatus, under a condition of the key exchange where the first round trip time RTTL is equal to or less than a first threshold value;
• and
• a data transmitting step of transmitting data encrypted using a key exchanged in the authentication and key exchanging step to the receiving apparatus.

A communication method comprising:

• a first communication step of performing communication with a transmitting apparatus becoming a transmission origin of data by a first network;
• a second communication unit performing communication with a receiving apparatus becoming a transmission destination of data by a second network;
• and
• a round trip time information acquiring step of acquiring round trip time information regarding a round trip time RTTL with the receiving apparatus on the second network and transmitting the round trip time information to the transmitting apparatus.

A communication system comprising:

• a transmitting apparatus that transmits data;
• and
• a relay apparatus that performs communication with the transmitting apparatus by a first network and performs communication with a receiving apparatus becoming a transmission destination of data by a second network,
• where the relay apparatus acquires first round trip time information regarding a round trip time RTTL with the receiving apparatus on the second network and transmits the first round trip time information to the transmitting apparatus, and
• the transmitting apparatus performs authentication and key exchange with the receiving apparatus through the relay apparatus, under a condition of the key exchange where the first round trip time RTTL is equal to or less than a first threshold value, and transmits data encrypted using the exchanged key to the receiving apparatus.

A non-transitory computer readable medium including a computer program that is described with a computer readable format to cause a computer to function as:

• a data accumulating unit that accumulates transmission data;
• a communication unit that performs communication with a receiving apparatus becoming a transmission destination of data and a relay apparatus performing relay with the receiving apparatus;
• a first round trip time information acquiring unit that acquires first round trip time information regarding a first round trip time RTTL between the relay apparatus and the receiving apparatus;
• an authentication and key exchanging unit that performs authentication and key exchange with the receiving apparatus through the relay apparatus, under a condition of the key exchange where the first round trip time RTTL is equal to or less than a first threshold value;
• and
• a data transmitting unit that transmits data encrypted using a key exchanged by the authentication and key exchanging unit to the receiving apparatus.

A non-transitory computer readable medium including a computer program that is described with a computer readable format to cause a computer to function as:

• a first communication unit that performs communication with a transmitting apparatus becoming a transmission origin of data by a first network;
• a second communication unit that performs communication with a receiving apparatus becoming a transmission destination of data by a second network;
• and
• a round trip time information acquiring unit that acquires round trip time information regarding a round trip time RTTL with the receiving apparatus on the second network and transmits the round trip time information to the transmitting apparatus.