Steganographic data hiding using a device clock
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.
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.
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.
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 .