Method for generating rights object and device to perform the method, method for transmitting rights object and device to perform the method, and method for receiving rights object and device to perform the method

1. A method for transmitting a Rights Object (RO), comprising:

generating a password key by encrypting a password;

generating the RO using the password key; and

directly transmitting the RO from a first device to a second device,

wherein the RO is associated with content generated by the first device, and

wherein generating the RO comprises:

generating a Rights Object Encryption Key (REK) for encrypting a Content Encryption Key (CEK), and generating a Message Authentication Code (MAC) key for verifying the integrity of the RO;

encrypting the CEK using the REK; and encrypting the REK and the MAC key using the password key.

2. The method of claim 1 , wherein the password is shared between the first device and the second device.

3. The method of claim 1 , wherein if the RO is for content associated with a received RO, the received RO being received from a Rights Issuer (RI), the CEK is a CEK included in the received RO.

4. The method of claim 1 , wherein the method further comprises generating the CEK for encrypting content associated with the RO.

5. The method of claim 1 , wherein the RO comprises an <ro> element and a <mac> element signed with the MAC key, the <ro> element comprising an Identifier (ID) field with a device ID, a first encryption key field comprising the encrypted CEK, and a second encryption key field comprising the encrypted MAC key and the encrypted REK.

6. The method of claim 1 , wherein generating the password key comprises generating the password key using a password-based encryption method of Public-Key Cryptography Standard (PKCS) #5.

7. A device to generate a Rights Object

(RO), comprising:

a user input portion to receive a password;

a controller to generate a password key by encrypting the password, and to generate the RO using the password key; and

a communication module to directly transmit the RO from the device to a receiving device,

wherein the RO is associated with content generated by the device, and

wherein the controller generates a Rights Object Encryption Key (REK) for encrypting a Content Encryption Key (CEK), generates a Message Authentication Code (MAC) key for verifying the integrity of the RO, encrypts the CEK using the REK, and encrypts the REK and the MAC key using the password key.

8. The device of claim 7 , wherein the password is shared between the device and the receiving device.

9. The device of claim 7 , wherein if the RO is for content associated with a received RO, the received RO being received by the device from a Rights Issuer (RI), the CEK is a CEK included in the received RO.

10. The device of claim 7 , wherein the controller generates the CEK for encrypting content associated with the RO.

11. The device of claim 7 , wherein the RO comprises an <ro> element and a <mac> element signed with the MAC key, the <ro> element comprising an Identifier (ID) field with a device ID, a first encryption key field comprising the encrypted CEK, and a second encryption key field comprising the encrypted MAC key and the encrypted REK.

12. The device of claim 7 , wherein the controller generates the password key using a password-based encryption method of Public-Key Cryptography Standard (PKCS) #5.

13. A method for receiving a Rights Object (RO), comprising:

directly receiving the RO at a first device from a second device;

generating a password key by encrypting a password shared between the first device and the second device; and

interpreting the RO using the password key,

wherein the RO is associated with content generated by the second device, and

wherein interpreting the RO comprises:

decrypting an encrypted Message Authentication Code (MAC) key and an encrypted Rights Object Encryption Key (REK) included in the RO using the password key;

decrypting an encrypted Content Encryption Key (CEK) included in the RO using the decrypted REK; and

verifying integrity of the RO using the decrypted MAC key.

14. The method of claim 13 , further comprising:

decrypting content associated with the RO using the decrypted CEK.

15. The method of claim 13 , wherein generating the password key comprises generating the password key using a password-based encryption method of Public-Key Cryptography Standard (PKCS) #5.

16. A device to receive a Rights Object (RO), comprising:

a communication module to directly receive the RO from a transmitting device;

a storage to store a password shared with the transmitting device; and

a controller to generate a password key by encrypting the password, and to interpret the RO using the password key,

wherein the RO is associated with content generated by the transmitting device, and

wherein the controller decrypts an encrypted Message Authentication Code (MAC) key and an encrypted Rights Object Encryption Key (REK) included in the RO using the password key, decrypts an encrypted Content Encryption Key (CEK) included in the RO using the decrypted REK, and verifies integrity of the RO using the decrypted MAC key.

17. The device of claim 16 , wherein the controller decrypts content associated with the RO using the decrypted CEK.

18. The device of claim 16 , wherein the controller generates the password key using a password-based encryption method of Public-Key Cryptography Standard (PKCS) #5.