Data transmission apparatus, data reception apparatus, data transmission method, and data reception method

A data reception apparatus for receiving data protected by a copyright protection mechanism for inhibiting simultaneous existence of data at both a source and a sink of the movement from a first apparatus via a computer network, the data reception apparatus comprising:

• a key exchange unit that exchanges an encryption key used to encrypt and decrypt the data with a second apparatus;
• a first control unit that (i) controls the key exchange unit to start the key exchange when a request to reserve memory area for storing the data is received from the first apparatus and (ii) determines whether or not it is necessary to perform the key exchange with the second apparatus;
• and
• a second control unit that (i) reserves the memory area as requested after completion of the key exchange performed by the key exchange unit, (ii) transmits a notification of the completion of the reservation of the memory area to the second apparatus and (iii) reserves resources as requested immediately when the first control unit determines that the key exchange is not necessary to be performed.

A data reception apparatus for receiving data protected by a copyright protection mechanism for inhibiting simultaneous existence of data at both a source and a sink of the movement from a first apparatus via a computer network, the data reception apparatus comprising:

• a key exchange unit that exchanges an encryption key with a second apparatus, the encryption key being used for encrypting and decrypting the data;
• a first control unit that reads only an area where information for the key exchange performed by the key exchange unit is stored when reception of encrypted data provided by encrypting the data is started;
• a second control unit that controls the key exchange unit to start the key exchange using the information concerning the second apparatus stored in the area read by the first control unit;
• and
• a third control unit that starts reading an area where the encrypted data provided by encrypting the data is stored, after completion of the key exchange performed by the key exchange unit.