Method and system for copy-prevention of digital copyright works

• US 6,978,370 B1
• Filed: 03/23/1999
• Issued: 12/20/2005
• Est. Priority Date: 09/03/1996
• Status: Expired due to Fees

• Current Assignee: Irdeto USA Incorporated (MultiChoice Group Ltd.)
• Original Assignee: Cryptography Research, Inc. (Rambus Inc.)
• Inventors: Kocher, Paul C.
• Primary Examiner(s): Vu, Kim
• Assistant Examiner(s): TRUONG, THANHNGA B
• Application Number:
  US09/274,496
• Time in Patent Office: 2,464 Days
• Field of Search: 713/193, 713/161, 713/176, 713/168, 705/51, 705 57- 59, 380/201
• US Class Current: 713/176
• CPC Class Codes: G06F 21/16 Program or content traceability, e.g. by watermarking
• CPC Class Codes: H04L 2209/04 Masking or blinding
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 2209/605 Copy protection
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467

Abstract

Methods and apparati for marking digital material and for detecting marks therein. For mark detection, the material is divided into a plurality of blocks, to which a non-collision resistant compression function is applied. Compression outputs are placed in a shift register, whose value is tested for predetermined values or patterns. Mark embedding may be performed by modifying the data (for example by altering low-order bits and other non-critical regions) such that the outputs of the compression operation, when used as an input to the shift register, yield a predetermined value or pattern. A Hamming Majority operation, computed as the most common bit in a block, may be used as the compression operation, enabling marking and mark detection with material of virtually all types and formats. Mark detection technology may be implemented in media writers and other devices to determine whether the digital material is copyrighted or otherwise protected. An override capability is provided to allow authorized parties to bypass the protection.

Claims

1. A method for marking digital data to prevent the data from being copied or transmitted without authorization, the method comprising the steps of:

selecting a global copyright mask M;

generating an authenticator Y;

using an electronic computing device, generating a content override mask X derived from Y using a one-way cryptographic function;

selecting a data mask S to be a combination of X and M;

using the data mask S to create marked data from the digital data; and

transferring the marked data and Y to an entity configured to prevent copying or transmitting the marked data when the result of performing the one-way cryptographic function on Y is not detected in the marked data.

2. The method of claim 1 wherein the marked data includes additional embedded protection fields describing at least one action authorized by the data mask S.

3. The method of claim 1 wherein the marked data is compressed data.

4. The method of claim 1 wherein the marked data is in encrypted form.

5. The method of claim 1 wherein the marked data is allowed to be copied or transmitted when M is not found within the marked data.

6. The method of claim 1 wherein:

a first party performs the steps of selecting M, generating Y, generating X, and selecting S; and

the first party sends the marked data to a second party by supplying Y to a sending device associated with said first party.

7. The method of claim 6 wherein:

the first party sends Y to the second party;

the second party feeds Y to a writing device associated with the second party, enabling the marked data to be copied or transmitted by the second party once only; and

the writing device inhibits further propagation of Y, thereby preventing the marked data from being copied or transmitted more than once.

8. The method of claim 1 wherein the marked data includes executable program code.

9. A computer-implemented method for determining whether a requested action is authorized to be performed on some digital content, said method comprising the steps of:

receiving a request for an action to be performed on digital content;

applying a non-collision-resistant compression function to a plurality of portions of said digital content;

applying a one-way cryptographic function to an authenticator value;

determining whether the result of applying said one-way function is represented in results of said applications of said compression function; and

when said determining step finds that the result of applying said one-way function is so represented, allowing said requested action to be performed.

10. The method of claim 9 wherein said requested action includes making a copy of said digital content.