Optical disk authenticity checking based on precision of a physical feature

• US 6,775,227 B2
• Filed: 11/09/2001
• Issued: 08/10/2004
• Est. Priority Date: 09/07/2001
• Status: Expired due to Term

• Current Assignee: Nintendo Company Limited
• Original Assignee: Nintendo Company Limited
• Inventors: Watanabe, Atsushi, Nishiumi, Satsoshi
• Primary Examiner(s): PATEL, GAUTAM
• Application Number:
  US09/986,646
• Publication Number:
  US 20030048718A1
• Time in Patent Office: 1,005 Days
• Field of Search: 369/275.3, 369/53.21, 369/47.2, 369/47.21, 369/59.25, 369/30.04
• US Class Current: 369/275.3
• CPC Class Codes: G11B 19/122 involving the detection of an identification or authentication mark record carriers indicating unauthorised or prior use G11B23/28
• 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 20/00173 wherein the origin of the content is checked, e.g. determining whether the content has originally been retrieved from a legal disc copy or another trusted source
• CPC Class Codes: G11B 23/281 by changing the physical properties of the record carrier
• CPC Class Codes: G11B 7/007 Arrangement of the information on the record carrier, e.g. form of tracks , actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track

Abstract

An optical disk includes a feature forming area 11 and a criterion recording area 12. The feature forming area 11 is an area provided with physical features used for determining whether it is an authorized optical disk or not. The criterion recording area 12 is an area having recorded therein the data of a determination criterion, i.e., a criterion by which it is determined whether the optical disk has been produced in an authorized manner or not on the basis of the physical feature. An optical disk reproduction apparatus detects the physical features provided in the feature forming area 11, and reads the determination criterion recorded in the criterion recording area 12. Furthermore, based on the determination criterion which has been read, the optical disk reproduction apparatus determines whether or not the detected physical features are those provided for an authorized optical disk. Thus, the optical disk reproduction apparatus can determine whether or not the optical disk has been copied in an unauthorized manner.

Claims

1. An optical disk for use with an optical disk reproduction apparatus that determines whether said optical disk was produced in an authorized manner, said optical disk comprising:

data sectors providing readable data content,

at least one physical feature different from said data sectors, said physical feature being formed with a certain precision and being checked, when the optical disk is in use, by the optical disk reproduction apparatus for determining whether said optical disk has been produced in an authorized manner, and

a criterion recording area having a determination criterion parameter recorded therein, said determination criterion parameter specifying a minimum precision for determining authenticity of said optical disk, such that the optical disk reproduction apparatus determines said optical disk to have been produced in an authorized manner if the precision of said physical feature as detected by the optical disk reproduction apparatus exceeds the minimum precision specified by said determination criterion parameter.

2. The optical disk according to claim 1, wherein the criterion recording area is writable, and

the determination criterion parameter recorded in the criterion recording area is specified based on the physical feature.

3. The optical disk according to claim 1, wherein the optical disk includes a plurality different physical features, and

the criterion recording area includes a plurality of determination criterion parameters recorded therein, the plurality of determination criterion parameters being associated with the corresponding plurality of physical features.

4. The optical disk of claim 1 wherein said data sectors are arranged in recording tracks on said optical disk, and said physical feature comprises an array of pits formed between said recording tracks.

5. The optical disk of claim 1 wherein said optical disk includes inner and outer peripheries and plural recording tracks disposed between said inner and outer peripheries, said data sectors being stored within said recording tracks, said physical feature being disposed on at least one of said inner and outer peripheries.

6. An optical disk reproduction apparatus for reproducing data recorded on an optical disk including data sectors providing readable data content, said optical disk reproduction apparatus comprising:

a feature detection section for detecting a physical feature distinct from said data sectors, said physical feature being used for determining authenticity of said optical disk,

a criterion reading section for reading from the optical disk a determination criterion parameter specifying a minimum precision, and

a determination section coupled to said feature detecting section and said criterion reading section, said determination section determining authenticity of said optical disk by;

detecting a precision with which said physical feature is formed; and

comparing the detected precision of said physical feature against the minimum precision specified by said determination criterion parameter, such that said optical disk reproduction apparatus determines said optical disk to have been produced in an authorized manner if the detected precision of said physical feature exceeds the minimum precision specified by said determination criterion parameter.

7. The optical disk reproduction apparatus according to claim 6, further comprising a reproduction section for reproducing said data content recorded on the optical disk data sectors only if the determination section determines the optical disk was produced in an authorized manner.

8. The optical disk reproduction apparatus according to claim 7, wherein the determination section performs a sequence of plural checks to determine whether the optical disk was produced in an authorized manner, and

upon the determination section determining, in response to at least a first check that the optical disk was produced in an authorized manner, the reproduction section beginning reproduction of the data contents before the feature detection section completes said sequence of plural checks.

9. The optical disk reproduction apparatus of claim 6 wherein said physical feature is unencrypted.

10. An optical disk recording apparatus for recording data on an optical disk of the type having data sectors providing data content to be read by an optical disk reproduction apparatus, said optical disk recording apparatus comprising:

a data recording section for forming the data sectors on the optical disk;

a feature formation section for forming at least one physical feature different from said data sectors, said physical feature being formed with a certain precision and being checked, when the optical disk is in use, by the optical disk reproduction apparatus for determining whether said optical disk has been produced in an authorized manner, and

a criterion recording section for recording onto the optical disk a determination criterion parameter specifying a minimum precision for determining authenticity of said optical disk, such that the optical disk reproduction apparatus determines said optical disk to have been produced in an authorized manner if the precision of said physical feature as detected by the optical disk reproduction apparatus exceeds the minimum precision specified by said determination criterion parameter.

11. The optical disk recording apparatus according to claim 10, further comprising a determination criterion section for specifying the determination criterion parameter based at least in part on the physical feature on the optical disk, and

the criterion recording section records the specified determination criterion parameter in a subsequently-writable area of the optical disk.

12. The optical disk recording apparatus according to claim 10, wherein the optical disk is prefabricated with at least one said physical feature for inspection purposes, and the determination criterion section specifies the determination criterion parameter based at least in part on the physical feature formed on a prefabricated optical disk.

13. A method for determining whether an optical disk to be reproduced is authentic, the optical disk including data sectors providing readable data content,

a feature detection step of detecting a physical feature distinct from said data sectors, said physical feature being used for determining authenticity of said optical disk,

a criterion reading step of reading from the optical disk a determination criterion parameter specifying a minimum precision, and

a determination step of determining authenticity of said optical disk by:

detecting a precision with which said physical feature is formed; and

comparing the detected precision of said physical feature against the minimum precision specified by said determination criterion parameter, such that said optical disk is determined to have been produced in an authorized manner if the detected precision of said physical feature exceeds the minimum precision specified by said determination criterion parameter.

14. A method for producing an optical disk capable of being tested for authenticity by an optical disk reproduction apparatus, the optical disk being of the type having data sectors providing data content to be read by an optical disk reproduction apparatus, comprising:

a data recording step of forming the data sectors on the optical disk;

a feature formation step of forming at least one physical feature different from said data sectors, said physical feature being formed with a certain precision and being checked, when the optical disk is in use, by the optical disk reproduction apparatus for determining whether said optical disk has been produced in an authorized manner,

a criterion recording step of recording onto the optical disk a determination criterion parameter specifying a minimum precision for determining authenticity of said optical disk, such that the optical disk reproduction apparatus determines said optical disk to have been produced in an authorized manner if the precision of said physical feature as detected by the optical disk reproduction apparatus exceeds the minimum precision specified by said determination criterion parameter.

15. The method for producing an optical disk according to claim 14, further comprising a criterion parameter deciding step deciding the determination criterion parameter based at least in part on the physical feature formed by the feature formation step, and

the criterion recording step records the determination criterion parameter in a subsequently-writable area of the optical disk.

16. The method for producing an optical disk according to claim 14, wherein the optical disk is prefabricated with the physical feature thereon the method further comprising a criterion parameter deciding step of deciding the determination criterion parameter based at least in part on the physical feature form on the prefabricated optical disk.