Method for stega-cipher protection of computer code

• US 5,745,569 A
• Filed: 01/17/1996
• Issued: 04/28/1998
• Est. Priority Date: 01/17/1996
• Status: Expired due to Term

• Current Assignee: Wistaria Trading Inc.
• Original Assignee: The Dice Company
• Inventors: Cooperman, Marc, Moskowitz, Scott A.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US08/587,943
• Time in Patent Office: 832 Days
• Field of Search: 380/2, 380/4, 380/9, 380/21, 380/23, 380/25, 380/28, 380/49, 380/50, 380/54, 380/59, 283/73, 283/113, 283/17
• US Class Current: 705/58
• CPC Class Codes: G06F 21/16 Program or content traceability, e.g. by watermarking
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant

Abstract

A method for protecting computer code copyrights by encoding the code into a data resource with a digital watermark. The digital watermark contains licensing information interwoven with essential code resources encoded into data resources. The result is that while an application program can be copied in an uninhibited manner, only the licensed user having the license code can access essential code resources to operate the program and any descendant copies bear the required license code.

Claims

1. A method for copy protection of computer software, the computer software including executable code and a non-executable digital sample, said method comprising the steps of:

identifying a portion of the executable code to be encoded;

generating an encoded code resource from the identified portion of the executable code; and

embedding the encoded code resource in the non-executable digital sample.

2. The method of claim 1, further comprising the step of requiring a predetermined key to decode the encoded code resource prior to execution of the executable code.

3. The method of claim 2, further comprising deriving the predetermined key from licensing information associated with the computer software.

4. The method of claim 3, wherein the licensing information is selected from a group comprising an owning organization name, a personal owner name, an owner address, a license code, a software serial number, a distribution parameter, an architectural requirement, a price parameter, and a software metering parameter.

5. The method of claim 1, further comprising the step of transferring the non-executable digital sample with the embedded encoded code resource to a user of the computer software.

6. The method of claim 5, wherein said transferring step further comprises storing the non-executable digital sample with the embedded encoded code resource on a storage medium selected from a group comprising a soft-sector magnetic disk, a hard-sector magnetic disk, a magnetic tape, a CD-ROM disc, a CD-R disc, a digital video disk, a magneto-optical disk and a memory cartridge.

7. The method of claim 5, wherein said transferring step further comprises transmitting the non-executable digital sample with the embedded encoded code resource over a transmission medium selected from a group comprising a telephone line, an SCSI, an Ethernet network, a token ring network, an ISDN, an ATM network, a TCP/IP network, an analog cellular network, a digital cellular network, a wireless network, a digital satellite, a cable network, a fiber optic network and an electric powerline network.

8. The method of claim 1, wherein the encoded code resource comprises a series of instructions for processing the non-executable digital sample.

9. The method of claim 8, wherein the computer software is installed on a computer system including a memory, said method further comprising the steps of:

decoding the encoded code resource; and

loading the executable code into the memory of the computer system for execution.

10. A method for copy protection of computer software to be provided to an authorized user, the computer software including a plurality of code resources and a plurality of data resources, wherein each of the plurality of code resources includes a set of executable instructions, said method comprising the steps of:

selecting a code resource to be encoded;

using information relating to the authorized user to associate the selected code resource with a data resource; and

encoding the selected code resource within the associated data resource.

11. The method of claim 10, wherein said step of selecting a code resource comprises selecting a code resource required for operation of the computer software.

12. The method of claim 11, wherein said step of using information relating to the authorized user to associate the selected code resource with a data resource comprises generating a key from the information and using the key to map a code resource to a data resource.

13. The method of claim 12, wherein the key comprises a pseudo-random number string.

14. The method of claim 10, further comprising the step of storing a set of instructions in the computer software for enabling the authorized user to extract and decode the encoded code resource.

15. The method of claim 14, wherein the set of instructions includes instructions for determining in which of the plurality of data resources the selected code resource is encoded.

16. A method for copy protecting a software application executed by a computer system, the software application including a plurality of executable code resources loaded in a memory of the computer system, said method comprising the steps of:

determining an address within the memory of the computer system associated with each of the plurality of executable code resources; and

intermittently relocating each of the plurality of executable code resources to a different address within the memory of the computer during execution of the software application.

17. The method of claim 16, further comprising the step of modifying the software application to direct a call to an executable code resource to a memory scheduler.

18. The method of claim 17, wherein said step of intermittently relocating each of the plurality of executable code resources is performed in response to a call to an executable code resource received by the memory scheduler.

19. The method of claim 18, further comprising intermittently relocating the memory scheduler to a different address within the memory of the computer.

20. The method of claim 19, wherein said step of intermittently relocating the memory scheduler includes updating a reference to the memory scheduler in the memory of the computer system to reflect the different address within the memory of the computer.