Method and apparatus for preventing illegal copy or illegal installation of information of optical recording medium

• US 5,805,551 A
• Filed: 04/25/1997
• Issued: 09/08/1998
• Est. Priority Date: 04/18/1994
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Oshima, Mitsuaki, Gotoh, Yoshiho
• Primary Examiner(s): Edun, Muhammad N.
• Application Number:
  US08/845,794
• Time in Patent Office: 501 Days
• Field of Search: 369/59, 369/60, 369/47, 369/48, 369/49, 369/50, 369/54, 369/58, 369/32, 369/124, 360/48, 360/51
• US Class Current: 705/57
• CPC Class Codes: G06F 21/80 in storage media based on magnetic or optical technology, e.g. disks with sectors preventing unauthorised reproduction or copying of disc-type recordable media G11B20/00
• CPC Class Codes: G11B 11/10595 Control of operating function
• CPC Class Codes: G11B 13/04 magnetically or by magnetisation and optically or by radiation, for changing or sensing optical properties
• CPC Class Codes: G11B 13/045 combined recording by magnetic and optic means
• CPC Class Codes: G11B 19/02 Control of operating function, e.g. switching from recording to reproducing
• CPC Class Codes: G11B 19/04 Arrangements for preventing, inhibiting, or warning against double recording on the same blank or against other recording or reproducing malfunctions
• CPC Class Codes: G11B 19/12 by sensing distinguishing features of or on records, e.g. diameter end mark
• 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 20/00123 the record carrier being identified by recognising some of its unique characteristics, e.g. a unique defect pattern serving as a physical signature of the record carrier
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00557 wherein further management data is encrypted, e.g. sector headers, TOC or the lead-in or lead-out areas
• CPC Class Codes: G11B 20/00586 said format change concerning the physical format of the recording medium
• CPC Class Codes: G11B 20/00594 wherein the shape of recording marks is altered, e.g. the depth, width, or length of pits
• CPC Class Codes: G11B 20/00601 wherein properties of tracks are altered, e.g., by changing the wobble pattern or the track pitch, or by adding interruptions or eccentricity
• CPC Class Codes: G11B 20/1217 on discs
• CPC Class Codes: G11B 20/1252 for discontinuous data, e.g. digital information signals, computer programme data
• CPC Class Codes: G11B 2007/0013 for carriers having multiple discrete layers
• CPC Class Codes: G11B 2020/1259 with ROM/RAM areas
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 2220/211 : Discs having both read-only and rewritable or recordable areas containing application data; Partial ROM media
• CPC Class Codes: G11B 2220/213 : Read-only discs
• CPC Class Codes: G11B 2220/237 : having exactly two recording layers
• CPC Class Codes: G11B 2220/2525 : Magneto-optical [MO] discs
• CPC Class Codes: G11B 2220/2529 : Mini-discs
• CPC Class Codes: G11B 2220/2545 : CDs
• CPC Class Codes: G11B 2220/2587 : Laser Discs; Optical disc using analog recording
• CPC Class Codes: G11B 2220/65 : wherein solid state memory is used for storing indexing information or metadata
• CPC Class Codes: G11B 2220/655 : Memory in cassette [MIC]
• CPC Class Codes: G11B 2220/90 : Tape-like record carriers
• CPC Class Codes: G11B 23/282 : Limited play
• CPC Class Codes: G11B 23/284 : on the record carrier
• CPC Class Codes: G11B 27/034 : on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: G11B 27/105 : of operating discs
• CPC Class Codes: G11B 27/107 : of operating tapes
• CPC Class Codes: G11B 27/11 : by using information not detectable on the record carrier
• CPC Class Codes: G11B 27/24 : by sensing features on the record carrier other than the transducing track ; sensing signals or marks recorded by another method than the main recording
• CPC Class Codes: G11B 27/3027 : used signal is digitally coded
• CPC Class Codes: G11B 27/3063 : Subcodes
• CPC Class Codes: G11B 27/329 : on a disc [VTOC]
• CPC Class Codes: G11B 27/34 : Indicating arrangements indicating means incorporated in magazine or cassette G11B23/046 and G11B23/0875; indicating measured values in general G01D
• CPC Class Codes: G11B 27/36 : Monitoring, i.e. supervising the progress of recording or reproducing for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06
• CPC Class Codes: G11B 5/86 : Re-recording, i.e. transcribing information from one magnetisable record carrier on to one or more similar or dissimilar record carriers by varying the order of the information G11B27/029, G11B27/036
• CPC Class Codes: G11B 7/0037 : with discs
• CPC Class Codes: G11B 7/005 : Reproducing G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/0053 : Reproducing non-user data, e.g. wobbled address, prepits, BCA
• CPC Class Codes: G11B 7/00736 : Auxiliary data, e.g. lead-in, lead-out, Power Calibration Area [PCA], Burst Cutting Area [BCA], control information sector headers or adresses in prepits G11B7/00745; address data in track wobble G11B7/24082
• CPC Class Codes: G11B 7/24038 : Multiple laminated recording layers
• CPC Class Codes: G11B 7/26 : Apparatus or processes specially adapted for the manufacture of record carriers
• CPC Class Codes: G11B 7/28 : Re-recording, i.e. transcribing information from one optical record carrier on to one or more similar or dissimilar record carriers

Abstract

A recording and reproducing system for performing the reproduction using an optical recording medium. A physical feature of a ROM type disk is extracted and enciphered before being recorded in an optical disk. The cipher reproduced and converted into a plain text physical feature, which in turn, is compared with the physical feature information detected from the ROM disk. When both are coincident with each other, the operation of the system stops, thereby preventing the use of an illegally duplicated disk. The physical feature information, recorded on a magnetic recording layer 4 of the optical recording medium 2, is reproduced by an optical head 8 and compared with the information measured by a physical feature information detector, thereby detecting a duplicated medium.

Claims

1. An information reproducing system comprising means (17) for rotationally driving a disc-like optical recording medium (2) wherein information is recorded in the form of pits, an optical head (6) for reading out the recorded information from said optical recording medium, head-moving means (23) for making said optical head movable radially on said optical recording medium, and signal processing means for processing the information read out through said optical head, which system is characterized by including:

first physical information detecting means (743, 38,

     665) for detecting, on the basis of information read out through one of said optical head and a magnetic head, first physical feature information (532) which is representative of a physical feature including at least one of a two-dimensional pit arrangement and a pit configuration on said optical recording medium and which is enciphered and recorded at manufacturing of said optical recording medium;

decryption means (534) for deciphering the first physical feature information;

means (17a, 6, 38, 703a) for measuring a physical feature of said optical recording medium to detect second physical feature information;

check means (535) for checking said second physical feature information with said first physical feature information to make a decision as to whether or not both are in a specific relation to each other; and

control means (717,

     665) for, when the check means decides that said second physical feature information is not in the specific relation to said first physical feature information, stopping one of an operation of a specific program read out from said optical recording medium, the subsequent reading-out of information from said optical recording medium, and a given process of information, read out from the optical recording medium, the given process being practiced by said signal processing means, characterized in that said decryption means (534) converts a cipher into a plain text including said first physical feature information by using a disclosed key cipher system function (695b, 698b, 735h) for a decryption calculation (698b, 735s).

2. A system as defined in claim 1, characterised in that said second physical feature information detecting means detects a coordinate position of an optical recording signal on said optical recording medium by using coordinate position detecting means (335) for the detection of said second physical feature information.

3. A system as defined in claim 2, characterised in that said coordinate position detecting means obtains said second physical feature information by using angular position detecting means (17a) designed to detect an angular position of a specific recording signal on said recording medium.

4. A system as defined in claim 3, characterised in that said coordinate position detecting means has rotation detecting means (17) for detecting the rotation of a motor to detect an arrangement angle of said recording signal.

5. A system as defined in claim 4, characterised in that said rotation detecting means comprises detecting means (17a) for detecting a rotational pulse signal from said motor.

6. A system as defined in claim 5, characterised in that said rotation detecting means detects the rotation by using time division means (737) for time-dividing said rotational pulse signal from said motor to generate rotational pulses larger in number than the pulses of said rotational pulse signal.

7. A system as defined in claim 4, characterised in that said rotation detecting means detects the rotation on the basis of a rotational pulse signal from an FG (17) mounted on said motor.

8. A system as defined in claim 1, characterised in that said second physical feature information detecting means detects said second physical feature information by using tracking displacement detecting means (554) for detecting a tracking displacement.

9. A system as defined in claim 8, characterised in that said second physical feature information detecting means obtains said second physical feature information by using angular position detecting means (553) for detecting track displacements (554) of two or more specific recording signals placed on the adjacent tracks and disposed at the same angle and arrangement angles of said recording signals.

10. A system as defined in claim 8, characterised in that said tracking displacement detecting means (24a) detects a track displacement by using tracking amount detecting means (554) for detecting reflected light from an optical recording layer by a plurality of light-receiving sections (24b, 24c) divided in a tracking direction to obtain a tracking error signal.

11. An information reproducing system comprising means (17) for rotationally driving a disc-like optical recording medium (2) wherein information is recorded in the form of pits, an optical head (6) for reading out the recorded information from said optical recording medium, head-moving means (23) for making said optical head movable radially on said optical recording medium, and signal processing means for processing the information read out through said optical head, which system is characterized by including:

first physical information detecting means (743, 38,

     665) for detecting, on the basis of information read out through one of said optical head and a magnetic head, first physical feature information (532) which is representative of a physical feature including at least one of a two-dimensional pit arrangement and a pit configuration on said optical recording medium and which is enciphered and recorded at manufacturing of said optical recording medium;

decryption means (534) for deciphering the first physical feature information;

means (17a, 6, 38, 703a) for measuring a physical feature of said optical recording medium to detect second physical feature information;

check means (535) for checking said second physical feature information with said first physical feature information to make a decision as to whether or not both are in a specific relation to each other; and

control means (717,

     665) for, when the check means decides that said second physical feature information is not in the specific relation to said first physical feature information, stopping one of an operation of a specific program read out from said optical recording medium, the subsequent reading-out of information from said optical recording medium, and a given process of information, read out from the optical recording medium, the given process being practiced by said signal processing means, characterized in that said second physical feature information detecting means is equipped with pit depth detecting means (555) for detecting a pit depth of a specific recording signal to detect said second physical feature information.

12. A system as defined in claim 11, characterised in that said pit depth detecting means (555) detects a shallow pit area, in which pits are shallow in depth, by using a multi-level slicer (555b) having two or more slice levels.

13. A system a s defined in claim 12, characterised in that said pit depth detecting means (555) detects a second pit group (560c) recorded after a first pit group (561a) for a specific recording signal, said first pit group having pits with a common depth, and said second pit group having pits which are shallower than pits of said first pit group.

14. A system as defined in claim 13, characterised in that a frame synchronizing signal (738) is used as said specific recording signal.

15. A system as defined in claim 12, characterised in that said pit depth detecting means reproduces a learning pit group (560a) of a first pit group to detect a first offset voltage (746) with a first slice level before setting said slice level at said first offset voltage to reproduce a second pit group (560b).

16. A system as defined in claim 12, characterised in that said pit depth detecting means (555) obtains said second physical feature information by measuring a pit length of a pit group satisfying a first slice level and a pit length of a pit group satisfying a second slice level.

17. A system as defined in claim 12, characterised in that, when a slice level for a small light quantity is set as a first slice level, said multi-level slicer (555b) receives detection signals of pits satisfying only said first slice level but not satisfying a second slice level, and said pit depth detecting means (555) obtains said second physical feature information by measuring the number of said detection signals by means of a counter (555c).

18. An information reproducing system comprising means (17) for rotationally driving a disc-like optical recording medium (2) wherein information is recorded in the form of pits, an optical head (6) for reading out the recorded information from said optical recording medium, head-moving means (23) for making said optical head movable radially on said optical recording medium, and signal processing means for processing the information read out through said optical head, which system is characterized by including:

first physical information detecting means (743, 38,

     665) for detecting, on the basis of information read out through one of said optical head and a magnetic head, first physical feature information (532) which is representative of a physical feature including at least one of a two-dimensional pit arrangement and a pit configuration on said optical recording medium and which is enciphered and recorded at manufacturing of said optical recording medium;

decryption means (534) for deciphering the first physical feature information;

means (17a, 6, 38, 703a) for measuring a physical feature of said optical recording medium to detect second physical feature information;

check means (535) for checking said second physical feature information with said first physical feature information to make a decision as to whether or not both are in a specific relation to each other; and

control means (717,

     665) for, when the check means decides that said second physical feature information is not in the specific relation to said first physical feature information, stopping one of an operation of a specific program read out from said optical recording medium, the subsequent reading-out of information from said optical recording medium, and a given process of information, read out from the optical recording medium, the given process being practiced by said signal processing means, characterized in that said second physical feature information detecting means (635) detects said second physical feature information with error signal detecting means (633) being used as physical feature information detecting means to detect the presence or absence of an error signal (632) of a specific recording signal in a specific address.

19. A system as defined in claim 18, characterised in that, when the number (535b) of said error signals of said specific recording signal indicated in said first physical feature information does not exceed a predetermined value (535b), said check means (535) issues a stop instruction.

20. An information reproducing system comprising means (17) for rotationally driving a disc-like optical recording medium (2) wherein information is recorded in the form of pits, an optical head (6) for reading out the recorded information from said optical recording medium, head-moving means (23) for making said optical head movable radially on said optical recording medium, and signal processing means for processing the information read out through said optical head, which system is characterized by including:

first physical information detecting means (743, 38,

     665) for detecting, on the basis of information read out through one of said optical head and a magnetic head, first physical feature information (532) which is representative of a physical feature including at least one of a two-dimensional pit arrangement and a pit configuration on said optical recording medium and which is enciphered and recorded at manufacturing of said optical recording medium;

decryption means (534) for deciphering the first physical feature information;

means (17a, 6, 38, 703a) for measuring a physical feature of said optical recording medium to detect second physical feature information;

check means (535) for checking said second physical feature information with said first physical feature information to make a decision as to whether or not both are in a specific relation to each other; and

control means (717,

     665) for, when the check means decides that said second physical feature information is not in the specific relation to said first physical feature information, stopping one of an operation of a specific program read out from said optical recording medium, the subsequent reading-out of information from said optical recording medium, and a given process of information, read out from the optical recording medium, the given process being practiced by said signal processing means, characterized in that said second physical feature information detecting means uses a special sign detecting means (640) as physical feature information detecting means and detects said second physical feature information by detecting that a special sign (639) which is not present in a first legal sign decode table in sign decode means exists in a specific recording signal area.

21. A system as defined in claim 20, characterised in that, when said special sign (639) is not present in said specific recording signal area indicated by said first physical feature information, said check means (535) outputs a stop instruction.

22. An information reproducing system comprising means (17) for rotationally driving a disc-like optical recording medium (2) wherein information is recorded in the form of pits, an optical head (6) for reading out the recorded information from said optical recording medium, head-moving means (23) for making said optical head movable radially on said optical recording medium, and signal processing means for processing the information read out through said optical head, which system is characterized by including:

first physical information detecting means (743, 38,

     665) for detecting, on the basis of information read out through one of said optical head and a magnetic head, first physical feature information (532) which is representative of a physical feature including at least one of a two-dimensional pit arrangement and a pit configuration on said optical recording medium and which is enciphered and recorded at manufacturing of said optical recording medium;

decryption means (534) for deciphering the first physical feature information;

means (17a, 6, 38, 703a) for measuring a physical feature of said optical recording medium to detect second physical feature information;

check means (535) for checking said second physical feature information with said first physical feature information to make a decision as to whether or not both are in a specific relation to each other; and

control means (717,

     665) for, when the check means decides that said second physical feature information is not in the specific relation to said first physical feature information, stopping one of an operation of a specific program read out from said optical recording medium, the subsequent reading-out of information from said optical recording medium, and a given process of information, read out from the optical recording medium, the given process being practiced by said signal processing means, characterized in that said second physical feature information detecting means has pit arrangement detecting means (747) for detecting pit arrangements on two or more tracks, adjacent to each other, in a specific area indicated by said first physical feature information of said recording medium.

23. A system as defined in claim 22, characterised in that said pit arrangement detecting means (747) detects an area in which pit arrangements on the adjacent two tracks are in phase or in antiphase with each other.

24. A system as defined in claim 23, characterised in that said pit arrangement detecting means (747) obtains said second physical feature information by detecting positional information of an inphase pit area in which the recording signal pits with the longest pit length are arranged to be in phase with each other.

25. A system as defined in claim 24, characterised by further comprising inphase/antiphase signal position detecting means (748) for detecting a position of an inphase pit area by using address information and a reproduced clock signal to obtain a portion of said second physical feature information (734).

26. A system as defined in claim 24, characterised in that said decryption means converts a first cipher into a plain text with a cipher decode function stored in an OS.

27. A system as defined in claim 23, characterised by further comprising a specific inphase signal detecting section (749) for detecting a specific inphase signal (654a) corresponding to a specific pit length on the basis of a detection signal of inphase/antiphase signal position detecting means (747).

28. A system as defined in claim 27, characterised in that said specific inphase signal detecting section (749) detects an inphase signal (654a) of a frame synchronizing signal as said specific inphase signal.

29. A system as defined in claim 23, characterised by further comprising inphase/antiphase signal position detecting means (747) for detecting inphase signals (654a, 654b) corresponding to inphase pit arrangements on adjacent three or more tracks.

30. A system as defined in claim 29, characterised in that said inphase/antiphase signal position detecting means (747) detects specific inphase signals (654a, 654b) on adjacent three tracks where the longest pits are disposed in phase as inphase signals.

31. A system as defined in claim 30, characterised by further comprising a specific inphase signal detecting section (749) for detecting an inphase signal (654a) of a frame synchronizing signal as said specific inphase signal.

32. A system as defined in claim 23, characterised by further comprising off-tracking means (646) provided in a tracking means (24) for tracking between two tracks to reproduce inphase signals or antiphase signals of pits of said two tracks, and further comprising inphase/antiphase signal detecting means (747) for detecting an inphase or antiphase area in which pit arrangements on said two tracks are in phase with each other to obtain said second physical feature information.

33. A system as defined in claim 29, characterised by further comprising off-tracking control means (646) responsive to an off-tracking switching signal from control means (10) to cause a light beam to be switch from a state of travelling one track to a state of travelling between two tracks to, reproduce inphase signals or antiphase signals of said two tracks so that said inphase/antiphase signal detecting means (747) detects said inphase signals or antiphase signals.

34. A system as defined in claim 33, characterised in that said off-tracking control means (24a, 646) inverts the polarity of a tracking servo of tracking means in accordance with said off-tracking switching signal to make switching to an off-tracking state in which said light beam travels between said two tracks.

35. A system as defined in claim 22, characterised in that said pit arrangement detecting means detects an area in which pit arrangements on adjacent two tracks are in phase with each other.

36. An information reproducing system comprising means (17) for rotationally driving a disc-like optical recording medium (2) wherein information is recorded in the form of pits, an optical head (6) for reading out the recorded information from said optical recording medium, head-moving means (23) for making said optical head movable radially on said optical recording medium, and signal processing means for processing the information read out through said optical head, which system is characterized by including:

first physical information detecting means (743, 38,

     665) for detecting, on the basis of information read out through one of said optical head and a magnetic head, first physical feature information (532) which is representative of a physical feature including at least one of a two-dimensional pit arrangement and a pit configuration on said optical recording medium and which is enciphered and recorded at manufacturing of said optical recording medium;

decryption means (534) for deciphering the first physical feature information;

means (17a, 6, 38, 703a) for measuring a physical feature of said optical recording medium to detect second physical feature information;

check means (535) for checking said second physical feature information with said first Physical feature information to make a decision as to whether or not both are in a specific relation to each other; and

control means (717,

     665) for, when the check means decides that said second physical feature information is not in the specific relation to said first physical feature information, stopping one of an operation of a specific program read out from said optical recording medium, the subsequent reading-out of information from said optical recording medium, and a given process of information, read out from the optical recording medium, the given process being practiced by said signal processing means, characterized by further comprising reproducing means for detecting a low-reflection section (740) producing a small reflected light quantity due to the presence of pits and a high-reflection section (741) having a higher reflectance than that of said low-reflection section due to the absence of pits, second low-reflection section detecting means (586) for detecting a second low-reflection section placed in an optical recording signal area (742) and having a lower reflectance than that of said first low-reflection section to produce a second reflected light quantity, and demodulating means (621) for demodulating a second low-reflection section detection signal of said second low-reflection section detecting means into a first digital signal.

37. A system as defined in claim 36, characterised in that level slicers having two or more slice levels are used so that said first optical recording signal is sliced with a first slice level in a first level slicer (586) to obtain said first digital signal from a first optical reproduced signal and a reproduced signal is sliced with a second slice level in a second level slicer (586), said second slice level corresponding to a light quantity smaller than that for said first slice level, whereby said second low-reflection section detecting means (586) detects said second low-reflection section.

38. A system as defined in claim 37, characterised by further comprising at least one of second low-reflection section pulse width detecting means (621e) for detecting the circumferential length of said second low-reflection section on the basis of said second low-reflection section detection signal due to said second low-reflection section detecting means (586) and said first optical reproduced signal due to said reproducing means (590) and second low-reflection section interval detecting means (621b) for detecting a circumferential interval of said second low-reflection section, said demodulating means (621) demodulating said first digital signal on the basis of a detection signal of said second low-reflection section interval detecting means.

39. A system as defined in claim 38, characterised in that, on the basis of the number of reproduction clock signals counted by a counter (598c), said second low-reflection section pulse width detecting means (621e) detects a pulse duration of a detection signal of said second low-reflection section and said second low-reflection section pulse interval detecting means (621b) detects an interval of said second low-reflection section detection signal.

40. A system as defined in claim 36, characterised in that said decryption means (534) obtains said first physical feature information by obtaining a first cipher from said first digital signal and by decrypting said first cipher.

41. A system as defined in claim 40, characterised in that said decryption means (534) encrypts said first cipher and converts at least said first physical feature information and an ID number (750) into plain texts.

42. A system as defined in claim 40, characterised by further comprising an ID outputting section (750) for obtaining and outputting an ID number, which is a plain text, from said first digital signal.

43. A system as defined in claim 40, characterised in that said demodulating means (621) outputs an ID number, which is a plain text or cipher, on the basis of said first digital signal, and further outputs a first secrete key, mathematically independent of said ID number, when a communication is established with a one direction function, and characterised by further comprising a calculation section (10) for enciphering secrete information with said first secrete key and a disclosed key cipher such as an RSA function to transmit said cipher, together with said ID number, through a communication section (664) to an external computer (633).

44. An information reproducing system comprising means (17) for rotationally driving a disc-like optical recording medium (2) wherein information is recorded in the form of pits, an optical head (6) for reading out the recorded information from said optical recording medium, head-moving means (23) for making said optical head movable radially on said optical recording medium, and signal processing means for processing the information read out through said optical head, which system is characterized by including:

first physical information detecting means (743, 38,

     665) for detecting, on the basis of information read out through one of said optical head and a magnetic head, first physical feature information (532) which is representative of a physical feature including at least one of a two-dimensional pit arrangement and a pit configuration on said optical recording medium and which is enciphered and recorded at manufacturing of said optical recording medium;

decryption means (534) for deciphering the first physical feature information;

means (17a, 6, 38, 703a) for measuring a physical feature of said optical recording medium to detect second physical feature information;

check means (535) for checking said second physical feature information with said first physical feature information to make a decision as to whether or not both are in a specific relation to each other; and

control means (717,

     665) for, when the check means decides that said second physical feature information is not in the specific relation to said first physical feature information, stopping one of an operation of a specific program read out from said optical recording medium, the subsequent reading-out of information from said optical recording medium, and a given process of information, read out from the optical recording medium, the given process being practiced by said signal processing means, characterized in that said decryption means (534) converts a first cipher, encrypted with a disclosed key cipher system function, into a plain text including said first physical feature information.

45. A system as defined in claim 44, characterised in that said decryption means enciphers said first cipher by using an integer d≧

256 bits as a secrete key and converts said first cipher into said plain text by using an integer n≧

256 bits as a decode key and disclosed key.

46. A system as claimed in claim 45, characterised in that said decryption means uses an RSA function as said disclosed cipher system function.

47. A system as claimed in claim 46, characterised in that, when said first cipher is taken as C, said plain text is taken as M, said disclosed key is taken to be an integer n≧

256 bits and said secrete key is taken to be an integer d above 256 bits, said decryption means obtains said first physical feature information by decoding said plain M in accordance with an equation of M=Cemod n as a function of said first cipher C made by encrypting means, a disclosed integer e above 3 and said disclosed key n in accordance with an equation of C=Mdmod n.

48. A system as defined in claim 45, characterised in that said decryption means uses an elliptical function as said disclosed key cipher system function.

49. A system as defined in claim 44, characterised in that said decryption means reproduces a plain text conversion function recorded in said recording medium, and converts a reproduced cipher into a plain text with said plain text conversion function.

50. A system as defined in claim 44, characterised in that said decryption means obtains said first physical feature information by using cipher-plain text conversion means which converts a cipher reproduced from said recording medium into a plain text by using a cipher decode function stored in a memory section of a non-volatile RAM or ROM of said system.

51. A system as defined in claim 50, characterised in that a plain text conversion function group comprising a plurality of plain text conversion functions is stored in said memory section of said system, a reproduced cipher is converted into a plain text through a plurality of specific functions of said plain text conversion function group to obtain a plurality of plain text groups, and a stop instruction is issued except that all of said plain text groups are normally obtained.

52. A method of preventing an illegal copy of a disc-like optical recording medium or of preventing an illegal install of information on the disc-like optical recording medium, which comprises the steps of:

detecting on the basis of information read out from the optical recording medium first physical feature information (532) which is representative of a physical feature including at least one of a two-dimensional pit arrangement and pit configuration on said optical recording medium and which is encrypted and recorded by using a one direction function at manufacturing of said optical recording medium;

decrypting said first physical feature information;

measuring a physical feature of said optical recording medium to obtain second physical feature information;

checking said second physical feature information with said first physical feature information to make a decision as to whether or not both are in a specific relation to each other; and

when the check step decides that the second physical feature information is not in the specific relation to the first physical feature information, stopping the operation of a specific program read out from the optical recording medium, stopping at least one of the subsequent reading-out of information from the optical recording medium, and a given process of information read out from said optical recording medium, the given process being practiced by signal processing means.

53. A method of preventing an illegal copy of a disc-like optical recording medium or of preventing an illegal install of information on the disc-like optical recording medium, which comprises the steps of:

detecting first physical feature information (532) from said optical recording medium, said first physical feature information being indicative of a physical feature at least including a two-dimensional pit arrangement or a pit configuration on the optical recording medium, encrypted using a one direction function and recorded on said optical recording medium or an original record therefor so as to be distinguishable from main information to be recorded on said optical recording medium;

decrypting said first physical feature information;

measuring a physical feature of said optical recording medium to obtain a second physical feature information;

checking said second physical feature information with said first physical feature information to make a decision as to whether or not both are in a specific relation to each other; and

when the check step decides that said second physical feature information is not in the specific relation to said first physical feature information, stopping at least one of the operation of a specific program read out from said optical recording medium, the subsequent reading-out of information from the optical recording medium, and a given process of information, read out from the optical recording medium, said given process being practiced by signal processing means.