Hardware key-on-disk system for copy-protecting magnetic storage media

• US 4,577,289 A
• Filed: 12/30/1983
• Issued: 03/18/1986
• Est. Priority Date: 12/30/1983
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Comerford, Liam D., White, Steve R.
• Primary Examiner(s): Zache, Raulfe B.
• Application Number:
  US06/567,294
• Time in Patent Office: 809 Days
• Field of Search: 364/200 MS File, 364/900 MS File, 360/60
• US Class Current: 360/60
• 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 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 20/00094 involving measures which result in a restriction to authorised record carriers
• 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 20/00949 said intentional errors occurring due to bad sectors, which are either physically destroyed or which are declared defective in the defect management information

Abstract

A copy-protection scheme is implemented for software which may be stored on a magnetic storage medium such as a disk. The medium is comprised of sections which are divided into subsections, with an original having indicia on at least one subsection of at least one section that is not modifiable by the medium write process, with a copy having no such indicia, or having indicia in a different pattern. A product program may be stored on the medium, and is executable only if the particular medium is an original. A medium test program may also be stored on the particular medium, and is used to test if the medium is an original or a copy. The test program writes the sections with a test pattern which generates a change in the pattern of magnetic domains of the medium, a subsection at a time, with a subsection responding to the test pattern only in the absence of indicia thereon, to form a stored pattern on the given section. An expected pattern and the stored pattern are compared at least a subsection at a time to determine if corresponding subsections have a predetermined pattern of magnetic domains. The product program is executed only in response to the comparison determining that corresponding subsections have predetermined patterns of magnetic domains which is indicative of the presence of said indicia, and the particular medium being an original.

Claims

1. A method of determining by a computer if a particular magnetic medium comprised of sections which are divided into subsections is an original or a copy, with an original having indicia on at least one subsection of at least one section thereon that are not modifiable by the medium write process, and a copy not having said indicia, or having indicia in a different pattern than said indicia, including a product program which is to be executed only if the medium is an original, and a medium test program for performing said method to test if said particular medium is an original, said method comprising the steps of:

writing at least portions of said sections of said particular medium with a test pattern which generates a change in the pattern of magnetic domains in said medium at predetermined locations within said portions, said portions including at least said indicia-containing subsections, with a subsection in said portions responding to said test pattern only in the absence of indicia thereon, to form a stored pattern in said portions;

storing an expected pattern, which is indicative of the pattern which is expected to be read from said portions of an original medium including said indicia;

comparing said expected pattern with said stored pattern on at least a per subsection basis, to determine if predetermined subsections have the expected pattern of magnetic domains; and

executing said product program only in response to the comparison determining that the corresponding subsections have the expected pattern of magnetic domains, which is indicative of the presence of said indicia, thereby indicating that said particular medium is an original.

2. The method claimed in claim 1, wherein said particular magnetic medium is a disk.

3. The method claimed in claim 2, wherein said disk is a floppy disk.

4. The method claimed in claim 2, wherein said disk is a hard disk.

5. The method claimed in claim 1, wherein said particular magnetic medium is a magnetic tape.

6. The method claimed in claim 1, including the steps of:

storing a binary coded masking pattern in said portions of said particular medium;

reading said masking pattern from said portions and storing said masking pattern prior to said test pattern being written therein; and

rewriting said masking pattern into said portions, subsequent to the reading of said stored pattern therefrom, to hide the operation used to determine if said particular medium is an original.

7. The method claimed in claim 6, wherein said particular medium is a disk.

8. The method claimed in claim 7, wherein said disk is a floppy disk.

9. The method claimed in claim 7, wherein said disk is a hard disk.

10. The method claimed in claim 6, wherein said particular medium is a magnetic tape.

11. A method of determining by a computer if a particular magnetic disk having tracks formed thereon which are divided into sectors is an original or a copy, with an original having indicia on at least one sector of at least one track thereon that are not modifiable by the disk write process, and a copy not having said indicia, or having indicia in a different pattern than said indicia, including a product program which is to be executed only if the disk is an original, and a disk test program stored performing said method to test if said particular disk is an original, said method comprising the steps of:

writing at least portions of said tracks of said particular disk with a test pattern which generates a change in the pattern of magnetic domains in said disk at predetermined bit locations within said portions, said portions including at least said indicia-containing sectors, with a bit location in said sectors responding to said test pattern only in the absence of indicia thereon, to form a stored pattern in said portions;

storing an expected pattern, which is indicative of the pattern which is expected to be read from said portions of an original disk including said indicia;

comparing said expected pattern with said stored pattern on at least a per bit location basis, to determine if predetermined locations have the expected pattern of magnetic domains; and

executing said product program only in response to the comparison determining that the predetermined locations have the expected pattern of magnetic domains, which is indicative of the presence of said indicia, thereby indicating that said particular disk is an original.

12. The method claimed in claim 11, wherein said disk is a floppy disk.

13. The method claimed in claim 11, wherein said disk is a hard disk.

14. The method claimed in claim 11, including the steps of:

storing a binary coded masking pattern in said portions of said disk;

reading said masking pattern from said portions and storing said masking pattern prior to said test pattern being written therein; and

rewriting said masking pattern into said portions, subsequent to the reading of said stored pattern therefrom, to hide the operations used to test if said disk is an original.

15. The method claimed in claim 14, wherein said disk is a floppy disk.

16. The method claimed in claim 14, wherein said disk is a hard disk.

17. A method of determining by a computer if a particular magnetic tape having records formed thereon which are divided into tracks is an original or a copy, with an original having indicia on at least one track of at least one record that are not modifiable by the tape write process, and a copy not having said indicia, or having indicia in a different pattern than said indicia, including a product program, which is to be executed only if the tape is an original, and a tape test program for performing said method to test if said particular tape is an original, said method comprising the steps of:

writing at least portions of said records of said particular tape with a test pattern which generates a change in the pattern of magnetic domains in said tape at predetermined bit locations within said portions, said portions including at least said indicia-containing tracks, with a bit location in said portions responding to said test pattern only in the absence of indicia thereon, to form a stored pattern in said portions;

storing an expected pattern, which is indicative of the pattern which is expected to be read from said portions of an original tape including said indicia;

comparing said expected pattern with said stored pattern on at least a per bit location basis, to determine if predetermined locations have the expected pattern of magnetic domains; and

executing said product program only in response to the comparison determining that the predetermined locations have the expected pattern of magnetic domains, which is indicative of the presence of said indicia, thereby indicating that said particular tape is an original.

18. The method claimed in claim 17, including the steps of:

storing a binary coded masking pattern in said portions of said magnetic tape;

reading said masking pattern from said portions and storing said masking pattern prior to said test pattern being written therein; and

rewriting said masking pattern into said portions, subsequent to the reading of said stored pattern therefrom, to hide the operation used to test if said particular tape is an original.

19. A method of determining by a computer if a particular magnetic disk having tracks formed thereon which are divided into sectors, with each sector being comprised of a plurality of bit storage locations, is an original or a copy, with an original disk having indicia on at least one bit storage location of at least one sector of at least one track that are not modifiable by the disk write process, with a copied disk not having said indicia, or having indicia in a different pattern than said indicia, including a product program, which is to be executed only if said disk is an original, and a disk test program for performing said method to test if said particular disk is an original, said method comprising the steps of:

storing a key pattern, which is a binary representation of the presence or absence of said indicia at predetermined locations of said at least one track of an original disk;

writing at least portions of said tracks of said particular disk with a test pattern which generates a change in the pattern of magnetic domains in said disk at predetermined bit locations within said portions, said portions including at least said indicia-containing bit storage locations, with a bit location in said portions responding to said test pattern only in the absence of indicia thereon, and reading out said portions to form a stored pattern, which is indicative of the presence or absence of said indicia at least at each bit storage location of said portions;

comparing said test pattern with said stored pattern on at least a per bit location basis to determine if predetermined locations have a pattern of indicia, to provide a first compare result;

comparing said key pattern with said first compare result on at least a per location basis to provide a second compare result which is indicative of whether or not said indicia on said sectors of said particular disk correspond with said indicia on said sectors of an original medium; and

executing said product program only in response to the second compare result indicating a predetermined location comparison of said key pattern and said first compare result, thereby indicating that said particular disk is an original.

22. The method claimed in claim 19, including the steps of:

storing a binary coded masking pattern in said portions of said particular disk;

reading said masking pattern from said portions and storing said masking pattern prior to said test pattern being written therein; and

rewriting said masking pattern into said portions, subsequent to the reading of said stored pattern therefrom, to hide the operation used to test if said particular disk is an original.

23. The method claimed in claim 22, wherein said disk is a floppy disk.

24. The method claimed in claim 22, wherein said disk is a hard disk.

20. The method claimed in 19, wherein said disk is a floppy disk.

21. The method claimed in 19, wherein said disk is a hard disk.

25. A software copy-protection apparatus, which is operable with a computer, comprising:

a particular magnetic medium having tracks formed thereon which are divided into sectors, with each sector being comprised of a plurality of bit storage locations, with an original medium having indicia on at least one bit storage location of at least one sector of at least one track that are not modifiable by the medium write process, with a copied medium not having said indicia, or having indicia in a different pattern than said indicia;

a product program which is to be executed only if said medium is an original;

means for writing at least portions of said tracks with a test pattern which generates a change in the pattern of magnetic domains in said medium at predetermined bit locations within said portions, said portions including at least said indicia-containing bit locations, with a given bit location in said portions responding to said pattern only in the absence of indicia thereon;

means for storing an expected pattern which is indicative of the pattern which is expected to be read from said portions of an original medium including indicia, in a first storage location;

means for reading out said portions and storing the read out data in a second storage location;

means for comparing the expected pattern stored in said first storage location with the data stored in said second storage location on at least a per bit corresponding storage location basis to determine if predetermined locations have the expected pattern of magnetic domains; and

means responsive to the comparison for executing said product program only in response to the comparison determining that predetermined locations on the medium have the expected pattern of magnetic domains, which is indicative of the presence of said indicia, thereby indicating that said particular medium is an original.

26. The combination claimed in claim 25, wherein said magnetic medium is a disk.

27. The combination claimed in claim 26, wherein said disk is a floppy disk.

28. The combination claimed in claim 26, wherein said disk is a hard disk.

29. The combination claimed in claim 26, including:

a binary coded masking pattern which is stored in said portions of said medium;

means for reading said masking pattern from said portions and storing it in a third storage location prior to said test pattern being written therein; and

means for rewriting said masking pattern into said portions, subsequent to the reading of said stored pattern therefrom, to hide the operation used to test if said particular medium is an original.

30. The combination claimed in claim 29, wherein said particular medium is a disk.

31. The combination claimed in claim 30, wherein said disk is a floppy disk.

32. The combination claimed in claim 30, wherein said disk is a hard disk.

33. A software copy-protection apparatus, which is operable with a computer, comprising:

a particular magnetic medium having records formed thereon which are divided into tracks, with each track being comprised of a plurality of bit storage locations, with an original medium having indicia on at least one bit storage location of at least one track of at least one record that are not modifiable by the medium write process, with a copied medium not having said indicia, or having indicia in a different pattern than said indicia;

a product program stored on said medium which is to be executed only if said medium is an original;

means for writing at least portions of said records with a test pattern which generates a change in the pattern of magnetic domains in said medium at predetermined bit locations in said portions, said portions including at least said indicia-containing bit locations, with a given bit location in said portions responding to said test pattern only in the absence of indicia thereon;

means for storing an expected pattern, which is indicative of the pattern which is expected to be read from said portions of an original medium including said indicia, in a first storage location;

means for reading out said portions and storing the read out data in a second storage location;

means for comparing the expected pattern stored in said first storage location with the data stored in said second storage location on a least a per bit corresponding basis to determine if predetermined locations have the expected pattern of magnetic domains; and

means responsive to the comparison for executing said product program only in response to the comparison determining that predetermined locations exhibit the expected pattern of magnetic domains, which is indicative of the presence of said indicia, thereby indicating that said particular medium is an original.

34. The combination claimed in claim 33, wherein said particular medium is a magnetic tape.

35. The combination claimed in claim 33, including:

a masking pattern which is stored in said portions of said particular medium;

means for reading said masking pattern from said portions and storing it in a third storage location prior to said test pattern being written therein; and

means for rewriting said masking pattern into said portions, subsequent to the reading of said stored pattern therefrom, to hide the operation used to test if said particular medium is an original.

36. The combination claimed in claim 35, wherein said particular medium is a magnetic tape.

37. A software copy-protection apparatus, which is operable with a computer, comprising:

a particular magnetic medium having tracks formed thereon which are divided into sectors, with each sector being comprised of a plurality of bit storage locations, with an original medium having indicia on at least one bit storage location of at least one sector of at least one track that are not modifiable by the medium write process, with a copied medium not having said indicia, or having indicia in a different pattern than said indicia;

a product program which is to be executed only if said medium is an original;

means for storing a key pattern in a first storage location, which is a binary representation indicative of the presence or absence of said indicia at predetermined locations of said at least one track of an original medium;

means for writing at least portions of said tracks of said medium with a test pattern which generates a change in the pattern of magnetic domains in said medium at predetermined bit locations within said portions, said portions including at least said indicia-containing bit storage location, with a bit location in said portions responding to said test pattern only in the absence of indicia thereon;

means for storing said test pattern in a second storage location;

means for reading out said portions and storing the read out data in a third storage location;

means for comparing the test pattern stored in said second storage location with the data stored in said third storage location on at least a per bit corresponding storage location basis to provide a first compare result;

means for comparing said key pattern, stored in said first storage location, with said first compare result on at least a per location basis to provide a second compare result which is indicative of whether or not said indicia on said sectors of said particular medium correspond with said indicia on said sectors of an original medium; and

means responsive to the second compare result for executing said product program only in response to the comparison determining that predetermined locations on the medium and the key pattern indicate a predetermined location comparison, thereby indicating that said particular medium is an original.

38. The combination claimed in claim 37, wherein said particular medium is a disk.

39. The combination claimed in claim 38, wherein said disk is a floppy disk.

40. The combination claimed in claim 38, wherein said disk is a hard disk.

41. The combination claimed in claim 37, including:

a masking pattern which is stored in said portions of said particular medium;

means for reading said masking pattern from said portions and storing it in a fourth storage location prior to said test pattern being written therein; and

means for rewriting said masking pattern into said portions, subsequent to the reading of said stored pattern therefrom, to hide the operation used to test if said particular medium is an original.

42. The combination claimed in claim 41, wherein said particular magnetic medium is a disk.

43. The combination claimed in claim 42, wherein said disk is a floppy disk.

44. The combination claimed in claim 42, wherein said disk is a hard disk.

45. A software copy-protection apparatus, which is operable with a computer, comprising:

a particular magnetic medium having records formed thereon which are divided into tracks, with each track being comprised of a plurality of bit storage locations, with an original medium having indicia on at least one bit storage location of at least one track of at least one record that are not modifiable by the medium write process, with a copied medium not having said indicia, or having indicia in a different pattern than said indicia;

a product program which is to be executed only if said medium is an original;

means for storing a key pattern in a first storage location, which is a binary representation indicative of the presence or absence of said indicia at predetermined locations of said at least one track of an original medium;

means for writing at least portions of said records of said medium with a test pattern which generates a change in the pattern of magnetic domains in said medium at predetermined bit locations within said portions, said portions including at least said indicia-containing bit storage locations, with a bit location in said portions responding to said test pattern only in the absence of indicia thereon;

means for storing said test pattern in a second storage location;

means for reading out said portions and storing the read out data in a third storage location;

means for comparing the test pattern stored in said second storage location with the data stored in said third storage location on at least a per bit corresponding storage location basis to provide a first compare result;

means for comparing said key pattern, stored in said first storage location, with said first compare result on at least a per location basis to provide a second compare result which is indicative of whether or not said indicia on said tracks of said particular medium correspond with said indicia on said tracks of an original medium; and

means responsive to the second compare result for executing said product program only in response to the comparison determining that predetermined locations on the medium and the key pattern indicate a predetermined location comparison, thereby indicating that said particular medium is an original.

46. The combination claimed in claim 45, wherein said particular medium is a magnetic tape.

47. The combination claimed in claim 45, including:

a masking pattern which is stored in said portions of said particular medium;

means for reading said masking pattern from said portions and storing it in a fourth storage location prior to said test pattern being written therein; and

means for rewriting said masking pattern into said portions, subsequent to the reading of said stored pattern therefrom, to hide the operation used to test if said particular medium is an original.

48. The combination claimed in claim 47, wherein said particular medium is a magnetic tape.

49. A method of forming a hardware key on a magnetic medium to indicate that said magnetic medium is an original and not a copy, said method comprising the step of:

introducing indicia into predetermined areas of said magnetic medium to create said key, with data read from said areas differing from data written to said areas, due to the presence of said indicia, as said indicia do not respond to a magnetic field by changing the pattern of magnetic domains therein.

50. The combination claimed in claim 49, wherein said indicia are comprised of one or more regions containing no magnetic material, such regions being therefore unaffected by the medium write process.

51. The combination claimed in claim 49, wherein said indicia are comprised of one or more permanently magnetized regions, such regions having the property that the material therein has a coercivity higher than the magnetic field used in the medium write process, such regions being therefore unaffected by the medium write process.

52. The combination claimed in claim 49, wherein said magnetic medium is a disk, having tracks formed thereon which are divided into sectors, with each sector being comprised of a plurality of bit storage locations, with said predetermined areas comprising at least one bit location of at least one sector of at least one track.

53. The combination claimed in claim 52, wherein the said disk is a floppy disk.

54. The combination claimed in claim 52, wherein the said disk is a hard disk.

55. The combination claimed in claim 49, wherein said magnetic medium is a magnetic tape, having records formed thereon which are divided into tracks, with each track being comprised of a plurality of bit storage locations, with said predetermined areas comprising at least one bit location of at least one track of at least one record.

56. The combination claimed in claim 50, wherein said magnetic medium is a disk, having tracks formed thereon which are divided into sectors, with each sector being comprised of a plurality of bit storage locations, with said predetermined areas comprising at least one bit location of at least one sector of at least one track.

57. The combination claimed in claim 56, wherein the said disk is a floppy disk.

58. The combination claimed in claim 56, wherein the said disk is a hard disk.

59. The combination claimed in claim 50, wherein said magnetic medium is a magnetic tape, having records formed thereon which are divided into tracks, with each track being comprised of a plurality of bit storage locations, with said predetermined areas comprising at least one bit location of at least one track of at least one record.

60. The combination claimed in claim 51, wherein said magnetic medium is a disk, having tracks formed thereon which are divided into sectors, with each sector being comprised of a plurality of bit storage locations, with said predetermined areas comprising at least one bit location of at least one sector of at least one track.

61. The combination claimed in claim 60, wherein said disk is a floppy disk.

62. The combination claimed in claim 60, wherein said disk is a hard disk.

63. The combination claimed in claim 51, wherein said magnetic medium is a magnetic tape, having records formed thereon which are divided into tracks, with each track being comprised of a plurality of bit storage locations, with said predetermined areas comprising at least one bit location of at least one track of at least one record.