Patent ID: 7970163

Claim:
A transmission device for use in a communication system including a reception device, the transmission device comprising: an obtaining unit configured to obtain moving picture data; an encryption unit configured to encrypt the moving picture data; a control unit configured (a) to inquire with the reception device about processing capability of a decryption unit which is configured to decrypt the encrypted moving picture data and included in the reception device, and (b) to change a transfer rate of the encrypted moving picture data to one of a first transfer rate and a second transfer rate based on the processing capability transmitted from the reception device to the transmission device, wherein the first transfer rate is higher than a normal transfer rate and the second transfer rate is lower than the normal transfer rate; and a transmission unit configured (a) to transmit the encrypted moving picture data to the reception device using the first transfer rate if the transfer rate of the encrypted moving picture data is changed to the first transfer rate, and (b) to transmit the encrypted moving picture data to the reception device using the second transfer rate if the transfer rate of the encrypted moving picture data is changed to the second transfer rate.