Methods and systems for encoding and protecting data using digital signature and watermarking techniques
View Patent ↗Systems and methods are provided for protecting and managing electronic data signals. In one embodiment a strong watermark is inserted in a data signal that is divided into a sequence of blocks, and a digital signature for each block is embedded in the signal via a watermark. The signal is then stored and distributed. When attempts are made to use or access the signal, the signal is checked for the presence of a watermark containing the digital signature for the desired portion of the signal. If the watermark is found, the digital signature is extracted and used to verify the authenticity of the desired portion of the signal. If not found, the signal is checked for the presence of the strong watermark, which if found causes the system to inhibit further use of the signal, and if not found further use of the signal is allowed.
1. A method for detecting modifications to an electronic file, the method performed by a system comprising a processor and a non-transitory computer-readable-medium storing instructions that when executed by the processor, cause the system to perform the method, the method comprising:
searching the electronic file for the presence of a signature-containing watermark;
if the signature-containing watermark is found:
retrieving a signature from the signature-containing watermark, and
using the signature to verify the authenticity of at least a portion of the electronic file;
if the signature-containing watermark is not found:
searching the electronic file for a second watermark;
if the second watermark is found, determining that that the electronic file has been modified;
if the second watermark is not found, granting a request to use the electronic file.
2. The method of claim 1 , wherein the second watermark is a strong watermark.
3. The method of claim 1 , wherein the second watermark is relatively more difficult to detect than the signature-containing watermark.
4. The method of claim 1 , wherein the signature-containing watermark is included in the at least a portion of the electronic file.
5. The method of claim 1 , wherein the electronic file comprises a series of multi-bit samples and the signature-containing watermark includes a quality indicator specifying a number of bits in each multi-bit sample that should be included when using the signature to verify the authenticity of the at least a portion of the electronic file.
6. The method of claim 1 , wherein the digital signature comprises an encrypted concatenation of a plurality of hash values, each hash value comprising the hash of a sub-portion of the at least a portion of the electronic file.
7. The method of claim 1 , wherein the method further comprises taking at least one defensive action relating to the use of the electronic file based on a determination that the electronic file has been modified.
8. The method of claim 7 , wherein the at least one defensive action comprises inhibiting use of the electronic file.
9. A system for detecting modifications to an electronic file, the system comprising:
a processor; and
a non-transitory computer-readable medium storing instructions that when executed by the processor, cause the system to:
search the electronic file for the presence of a signature-containing watermark;
if the signature-containing watermark is found:
retrieve a signature from the signature-containing watermark, and
use the signature to verify the authenticity of at least a portion of the electronic file;
if the signature-containing watermark is not found:
search the electronic file for a second watermark;
if the second watermark is found, determine that that the electronic file has been modified;
if the second watermark is not found, grant a request to use the electronic file.
10. The system of claim 9 , wherein the second watermark is a strong watermark.
11. The system of claim 9 , wherein the second watermark is relatively more difficult to detect than the signature-containing watermark.
12. The system of claim 9 , wherein the signature-containing watermark is included in the at least a portion of the electronic file.
13. The system of claim 9 , wherein the electronic file comprises a series of multi-bit samples and the signature-containing watermark includes a quality indicator specifying a number of bits in each multi-bit sample that should be included when using the signature to verify the authenticity of the at least a portion of the electronic file.
14. The system of claim 9 , wherein the digital signature comprises an encrypted concatenation of a plurality of hash values, each hash value comprising the hash of a sub-portion of the at least a portion of the electronic file.
15. The system of claim 9 , wherein the instructions, when executed by the processor, further cause the system to take at least one defensive action relating to the use of the electronic file based on a determination that the electronic file has been modified.
16. The system of claim 15 , wherein the at least one defensive action comprises inhibiting use of the electronic file.
17. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause a computer system to perform a method for detecting modifications to an electronic file, the method comprising:
searching the electronic file for the presence of a signature-containing watermark;
if the signature-containing watermark is found:
retrieving a signature from the signature-containing watermark, and
using the signature to verify the authenticity of at least a portion of the electronic file;
if the signature-containing watermark is not found:
searching the electronic file for a second watermark;
if the second watermark is found, determining that that the electronic file has been modified;
if the second watermark is not found, granting a request to use the electronic file.
18. The non-transitory computer-readable medium of claim 17 , wherein the second watermark is a strong watermark.
19. The non-transitory computer-readable medium of claim 17 , wherein the second watermark is relatively more difficult to detect than the signature-containing watermark.
20. The non-transitory computer-readable medium of claim 17 , wherein the signature-containing watermark is included in the at least a portion of the electronic file.
21. The non-transitory computer-readable medium of claim 17 , wherein the electronic file comprises a series of multi-bit samples and the signature-containing watermark includes a quality indicator specifying a number of bits in each multi-bit sample that should be included when using the signature to verify the authenticity of the at least a portion of the electronic file.
22. The non-transitory computer-readable medium of claim 17 , wherein the digital signature comprises an encrypted concatenation of a plurality of hash values, each hash value comprising the hash of a sub-portion of the at least a portion of the electronic file.
23. The non-transitory computer-readable medium of claim 17 , wherein the method further comprises taking at least one defensive action relating to the use of the electronic file based on a determination that the electronic file has been modified.
24. The non-transitory computer-readable medium of claim 23 , wherein the at least one defensive action comprises inhibiting use of the electronic file.