Steganographic data hiding using a device clock

• US 7,602,940 B2
• Filed: 10/05/2006
• Issued: 10/13/2009
• Est. Priority Date: 04/16/1998
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B., Carr, J. Scott
• Primary Examiner(s): TUCKER, WESLEY J
• Application Number:
  US11/545,081
• Publication Number:
  US 20070076916A1
• Time in Patent Office: 1,104 Days
• Field of Search: 382/100, 382/112, 382/115, 382/137, 382/232, 358/3.28, 358/444, 713/176, 345/630, 250/372, 705/26, 705/54, 709/723, 709/217, 380/218
• US Class Current: 382/100
• CPC Class Codes: G06F 16/41 Indexing; Data structures therefor; Storage structures
• CPC Class Codes: G06F 16/48 Retrieval characterised by using metadata, e.g. metadata not derived from the content or metadata generated manually
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G06T 2201/0202 whereby the quality of watermarked images is measured; Measuring quality or performance of watermarking methods; Balancing between quality and robustness
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32277 Compression
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/33357 Compression mode

Abstract

The presently claimed invention relates generally to methods and apparatus associated with steganographic encoding (e.g., data hiding). One claim recites a method including: obtaining plural-bit auxiliary information; and during communication between a first computer and a second computer over a network, modulating timing or phase of a clock signal generated by the first computer so as to steganographically hide the plural-bit auxiliary information in a communications signal sent between the first computer and the second computer. Of course, other claims and combinations are provided as well.

Claims

1. A method comprising:

obtaining plural-bit auxiliary information; and

during communication between a first computer and a second computer over a network, modulating timing or phase of a clock signal generated by the first computer so as to steganographically hide the plural-bit auxiliary information in a communications signal sent between the first computer and the second computer.

2. The method of claim 1 wherein the clock signal comprises a system clock signal generated by the first computer.

3. The method of claim 2 wherein the signal is varied in accordance with the plural-bit auxiliary information.

4. The method of claim 3 wherein a period of the signal is varied in accordance with the plural-bit, auxiliary information.

10. A programmed computing device storing instructions in memory, said instructions are executable by said programmed computing device to perform the acts of claim 1.

11. A computer readable media comprising instructions stored thereon to cause a multi-purpose computer processor to perform the acts of claim 1.

5. An apparatus comprising:

an input or memory to receive plural-bit auxiliary information there from;

a signal generator;

an output to communicate with a different apparatus over a network, the output communicating a clock signal generated by the signal generator, the signal generator modulating timing or phase of the clock signal so as to steganographically hide the plural-bit auxiliary information in the signal.

6. The apparatus of claim 5 wherein the signal generator comprises a system clock, and the signal comprises a system clock signal.

7. The apparatus of claim 6 wherein the signal is varied in accordance with the plural-bit auxiliary information.

8. The apparatus of claim 7 wherein a period of the signal is varied in accordance with the plural-bit auxiliary information.

9. The apparatus of claim 5 in which the signal generator is operating to modulate timing or phase of the signal so as to steganographically hide the plural-bit auxiliary information in the signal.