Method and apparatus for creating electronic water marks in digital data

• US 6,327,657 B1
• Filed: 05/07/1998
• Issued: 12/04/2001
• Est. Priority Date: 05/07/1998
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Goldberg, Randy G., Sachs, Richard M., Wetzel, William R.
• Primary Examiner(s): Hayes, Gail
• Assistant Examiner(s): Meislahn, Douglas J
• Application Number:
  US09/074,223
• Time in Patent Office: 1,307 Days
• Field of Search: 713/176
• US Class Current: 713/176
• CPC Class Codes: G10L 19/00 Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis in musical instruments G10H
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• 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 20/00891 embedded in audio data

Abstract

The present invention relates to a method and apparatus for placing a message in digital data. The message is placed by manipulating certain data bits in a way that does not severely corrupt the data. The data can be mu-law encoded, wherein a value of 1 is assigned to one representation of zero, and a value of 0 is assigned to the other representation of zero. In this case, a message is placed in the data using these assigned values of 1 and 0.

Claims

1. A method of placing a message in mu law encoded digital data, comprising:

(a) receiving digital data that is encoded with a technique that contains at least two representations of zero;

(b) receiving a message to be encoded in the digital data; and

(c) altering at least one representation of zero in a predictable way to encode the message within the digital data.

2. The method of claim 1, wherein the digital data is mu-law encoded, and further comprising:

(d) pseudorandomly altering at least one representation of zero.

3. The method of claim 1, wherein the digital data is mu-law encoded, and further comprising:

(d) assigning a value 1 to one representation of zero;

(e) assigning a value 0 to the other representation of zero; and

(f) placing a messasge in the data using the assigned value 1 and the assigned value 0.

4. An apparatus for placing a message in mu law encoded digital data, comprising:

(a) a processor;

(b) a port coupled to said processor;

(c) a memory coupled to said processor storing instructions adapted to be executed by said processor to

(i) receive digital data that is encoded with a technique that contains at least two representations of zero;

(ii) receive a message to be encoded in the digital data;

(iii) manipulate at least one representation of zero in a predictable way to encode the message within the digital data.

5. The apparatus in claim 4, wherein the received digital data in step (c)(i) is mu-law encoded data, and further comprising:

(d) a memory coupled to said processor storing instructions adapted to be executed by said processor to

(i) pseudorandomly alter the representations of zero.

6. The apparatus in claim 4, wherein the received digital data in step (c)(i) is mu-law encoded data, and further comprising:

(d) a memory coupled to said processor storing instructions adapted to be executed by said processor to

(i) assigning a value 1 to one representation of zero;

(ii) assigning a value 0 to the other representation of zero; and

(iii) placing a message in the data using the assigned value 1 and the assigned value 0.

7. A computer-readable medium that stores instructions adapted to be executed by a processor to perform the steps of:

(a) receiving digital data that is encoded with a technique that contains at least two representations of zero;

(b) receiving a message to be encoded in the digital data;

(c) manipulating at least one representation of zero in a predictable way to encode the message within the digital data.

8. The computer-readable medium of claim 7, wherein the digital data is mu-law encoded, and further storing instructions to be executed by a processor to perform the step of:

(d) pseudorandomly altering the representations of zero.

9. The computer-readable medium of claim 7, wherein the digital data is mu-law encoded, and further storing instructions to be executed by a processor to perform the steps of:

(d) assigning a value 1 to one representation of zero;

(e) assigning a value 0 to the other representation of zero; and

(f) placing a message in the data using the assigned value 1 and the assigned value 0.