Record carrier with distributed decryption information

• US 20060104449A1
• Filed: 06/26/2003
• Published: 05/18/2006
• Est. Priority Date: 07/05/2002
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Tuyls, Pim T., Van Dijk, Marten E., Kamperman, Franciscus L.A.J., Akkermans, Antonius H.M., Staring, Antonius A.M.
• Application Number:
  US10/519,068
• Publication Number:
  US 20060104449A1
• Time in Patent Office: Days
• US Class Current: 380/277
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00275 the key being stored on a chip attached to the record carrier
• CPC Class Codes: G11B 20/00492 wherein content or user data is encrypted
• CPC Class Codes: G11B 20/00876 wherein physical copy protection means are attached to the medium, e.g. holograms, sensors, or additional semiconductor circuitry

Abstract

The invention relates to a system for improved copy protection comprising a record carrier like a CD-RW+ or a DVD storing copy-protected information and a device for reading from and/or writing to the record carrier. For that the record carrier (1) has a first area (3) storing information (data), which is at least partly stored in encrypted form (EAK(data)), this part being called an asset (EAK(data)), and which includes a first part of decryption information (HCK, EDNK(HCK)), and the record carrier (1) further has a second area (4) storing a second part of decryption information (UCID), wherein both the first (HCK) and second (UCID) parts of decryption information serve in decrypting an asset (EAK(data)). Such distribution of decryption information over at least two areas of the record carrier may further be combined with additional safety mechanisms as e.g. hidden channels, encrypted keys, counter mechanisms, and revocation lists.

Claims

1. A record carrier (1) having a first area (3) storing information (data), which is at least partly stored in encrypted form (E_AK(data)), this part being called an asset (E_AK(data)), and which includes a first part of decryption information (HCK, E_DNK(HCK)), and the record carrier (1) further having a second area (4) storing a second part of decryption information (UCID), wherein both the first (HCK) and second (UCID) parts of decryption information serve in decrypting the asset (E_AK(data)).

2. A record carrier (1) as claimed in claim 1,

characterized in that

the first (3) and second areas (4) comprise storage media of a different physical kind.

3. A record carrier (1) as claimed in claim 1,

characterized in that

the second area (4) comprises a chip (4′

) for providing the store of the second area (4).

4. A record carrier (1) as claimed in claim 1,

characterized in that

a symmetric method using a first cryptographic key, called an asset key (AK), is used for asset en- and decryption, and in that

the asset key (AK) is stored in the second area (4) in an encrypted form, wherein for its encryption a symmetric encryption method has been used, this method employing a second cryptographic key (CIDK) in whose derivation both the first (HCK) and second (UCID) parts of decryption information have been used.

5. A record carrier (1) as claimed in claim 1,

characterized in that

a third cryptographic key, called a hidden-channel key (HCK), serves in the asset decryption, and in that

the hidden-channel key (HCK) is obtainable from the first part of decryption information (HCK, E_DNK(HCK)), in particular, that the hidden-channel key (HCK) coincides with the first part of decryption information (HCK) and that the first part of decryption information (HCK) is scrambled and/or encrypted within the information (data) stored in the first area (3).

6. A record carrier (1) as claimed in claim 3,

characterized in that

the chip (4′

) is designed for storing a first counter (C_i), and

the chip (4′

) is designed for allowing an reading and/or writing device read access to the first counter (C_i) but denying write access to it, and

the chip (4′

) is designed for changing the value of the first counter (C_i) each time the second part of decryption information (UCID) is read by an reading and/or writing device, and

the chip (4′

) is designed for storing a second counter (C_e) in an encrypted form, wherein both the first (HCK) and second (UCID) parts of decryption information serve in decrypting the second counter (C_e).

7. A record carrier (1) as claimed in claim 3,

characterized in that

the chip (4′

) is designed for checking the right of an reading and/or writing device to access the record carrier (1).

8. A record carrier (1) as claimed in claim 1,

characterized in that

the second area (4) is designed for storing user-specific settings serving in controlling the access of an reading and/or writing device to the record carrier (1) and/or in controlling the manner information being read from the record carrier (1) is presented by the reading and/or writing device to a user of the reading and/or writing device.

9. A device for reading from and/or writing to a record carrier (1) as claimed in claim 1, wherein the device is designed

for reading and/or writing the first part of decryption information (HCK, E_DNK(HCK)),

for reading and/or writing the second part of decryption information (UCID),

for reading and/or writing the asset (E_AK(data)),

optionally, for obtaining complete decryption information from both the first (HCK, E_DNK(HCK)) and second parts (UCID) of decryption information, and,

optionally, for decrypting and/or encrypting the asset (E_AK(data)) with the complete decryption information.

10. A device for reading and/or writing as claimed in claim 9,

characterized in that

the device is designed for accessing the first (3) and second areas (4) of the record carrier (1) in parallel.

11. A device for reading and/or writing as claimed in claim 9,

characterized in that

the device is designed for storing and maintaining a revocation list of identifiers (UCID), and in that

the device is designed for at least partly refusing a user of the device access to a record carrier (1) as claimed in claim 3 if the identifier (UCID) being stored on the record carrier (1) belongs to the revocation list.

12. A system for supporting copy protection, the system comprising a device as claimed in claim 9 and a record carrier (1) as claimed in claim 1.

13. A method for reading from and/or writing to a record carrier (1) as claimed in claim 1, with the steps:

reading and/or writing the first part of decryption information (HCK, E_DNK(HCK)),

reading and/or writing the second part of decryption information (UCID),

reading and/or writing the asset (E_AK(data)),

optionally, obtaining complete decryption information from both the first (HCK, E_DNK(HCK)) and second parts (UCID) of decryption information, and,

optionally, decrypting and/or encrypting the asset (E_AK(data)) with the complete decryption information.

14. A method for producing a record carrier (1) as claimed in claim 1, with the steps:

selecting an identifier (UCID), in particular, selecting an identifier (UCID) being different from the identifiers (UCID) having previously been selected in the method,

constructing the second part of decryption information (UCID) as comprising the identifier (UCID), and

producing the record carrier (1) with the thus constructed second part of decryption information (UCID) being stored on the second area (4) of the record carrier (1).