Patent ID: 8340061

Claim:
A first communication terminal, comprising: an information generation unit configured to convert secret information to redundant information, the redundant information being transmittable to a second communication terminal, and being useable by the second communication terminal to restore the secret information; a transmission unit configured to transmit the redundant information; a delivery management unit configured to manage transmission of the redundant information; and a reception unit configured to receive information transmitted from the second communication terminal, wherein: the delivery management unit is configured to cause the information generation unit to convert the secret information to higher redundant information that has a higher information amount and a higher bit error rate than the redundant information previously transmitted by the transmission unit and corresponding to the secret information, and to cause the transmission unit to transmit the higher redundant information to the second communication terminal, when a reply to the previously transmitted redundant information is not received by the reception unit from the second communication terminal.