CD-PROM

• US 5,563,947 A
• Filed: 12/20/1995
• Issued: 10/08/1996
• Est. Priority Date: 07/26/1993
• Status: Expired due to Fees

• Current Assignee: PDACO LIMITED
• Original Assignee: Elonex IP Holdings Limited
• Inventors: Kikinis, Dan
• Primary Examiner(s): Cain, David C.
• Application Number:
  US08/575,340
• Time in Patent Office: 293 Days
• Field of Search: 380/3, 380/4, 380/23, 380/25, 380/49, 380/50, 380/24, 360/60
• US Class Current: 705/51
• CPC Class Codes: G06F 12/1408 by using cryptography for digital transmission H04L9/00
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/629 to features or functions of an application
• 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: G06F 2221/2107 File encryption
• 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 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00253 wherein the key is stored on the record carrier
• CPC Class Codes: G11B 20/00492 wherein content or user data is encrypted
• CPC Class Codes: G11B 20/00528 wherein each title is encrypted with a separate encryption key for each title, e.g. title key for movie, song or data file
• CPC Class Codes: G11B 20/00659 involving a control step which is implemented as an executable file stored on the record carrier
• CPC Class Codes: G11B 20/00927 wherein said defects or errors are generated on purpose, e.g. intended scratches
• 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
• 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 2220/2545 CDs
• 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

Abstract

Encrypted data on a CD-PROM disk is managed by selectively encoding binary digital decryption keys onto the same disk in a separate data area. A decryption key or keys may be programmed onto the disk after manufacture, such as at the point of sale, by selectively obliterating the readability of bits in addressable sectors. A binary digital key is then later recognized as the result of a string of addressable sectors, with one or the other of readable or unreadable sectors being recognized as a logical 1 and the other as a logical 0. In an embodiment, a manufacturer may place several or all versions and features of a large program on a single CD-ROM, encrypted, and later provide keys to enable only selected ones of the features and versions for retrieval.

Claims

1. A method for providing security for stored data on a compact disk read-only memory (CD-ROM), comprising steps of:

(a) providing the stored data in an encrypted form in formatted sectors of a recording region on the CD-ROM, decrypting of the encrypted data requiring a keyword; and

(b) programming the keyword into a programming region on the CD-ROM by damaging the physical structure of the recording track in selected sectors in the programming region, the selected sectors spanning a region of the CD-ROM having a digital storage capacity of up to 500 megabytes.

2. The method of claim 1 wherein step (b) is performed by mounting the CD-ROM in a drive configured for rotating the CD-ROM, focusing a laser beam to converge on the physical features of the recording track, and controlling the laser beam to do the damaging.

3. The method of claim 1 further comprising a step of transporting the CD-ROMS with the encrypted data to point-of-sale retail outlets remote from a manufacturing and copying facility prior to the programming step.

4. The method of claim 1 wherein the recorded information comprises plural computer files, each encrypted in a fashion to require a unique digital keyword, and wherein each file is associated with a unique keyword programmed in the programming region.

5. The method of claim 4 wherein the plural computer files are executable code files, and the programming step comprises programming digital keywords for selectively activating individual ones of the executable code files for use by a host computer.

8. The method of claim 1 wherein, in the programming step, an executable computer program file is programmed into the programming region rather than a digital keyword, the sequence of physically damaged and undamaged sectors forming executable digital code.

10. The method of claim 1 wherein the keyword is formed non-sequentially by damaged sectors scattered over the programming region.

6. A method for providing access control to only selected files of multiple files stored on a compact disk read-only memory (CD-ROM), comprising steps of:

(a) recording the files in an encrypted form in formatted sectors of a recording region on the CD-ROM; and

(b) programming digital keywords for decrypting only the selected files into a programming region of the CD-ROM by damaging the physical structure of the recording track in selected sectors in the programming region, the selected sectors spanning a region of the CD-ROM having a digital storage capacity of up to 500 megabytes.

7. The method of claim 6 wherein the multiple files are application program files.

11. The method of claim 6 wherein the keyword is formed non-sequentially by damaged sectors scattered over the programming region.

9. An encrypted compact disk read-only memory (CD-ROM), comprising:

a recording region wherein information is recorded in an encrypted fashion responsive to a decryption algorithm based on a unique keyword; and

a programming region having formatted sectors along a data track wherein one or more decryption keywords are programmed by damaging the data track in selected sectors;

wherein the damaged sectors forming a keyword span a region of the CD-ROM having a digital storage capacity of up to 500 megabytes.

12. A CD-ROM as in claim 9 wherein the keyword is formed non-sequentially by damaged sectors scattered over the programming region.