Signatures for multiple encodings

• US 7,770,015 B1
• Filed: 05/20/2005
• Issued: 08/03/2010
• Est. Priority Date: 05/20/2005
• Status: Active Grant

• Current Assignee: Adobe Inc.
• Original Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Inventors: Goldman, Oliver, Young, Jeff
• Primary Examiner(s): COLIN, CARL G
• Application Number:
  US11/134,126
• Time in Patent Office: 1,901 Days
• Field of Search: 713/176, 713/177, 713/179, 713/180, 380/277
• US Class Current: 713/176
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

Digitally signing data for multiple encodings is disclosed. A first signature of the data is generated. A second signature of a second encoding of the data is generated. The first signature and the second signature are associated with the signed data.

Claims

1. A computer implemented method comprising:

generating a first signature of data using a processor, wherein the data is included in a first document, and wherein the first document has a first document encoding;

converting the first document from the first document encoding to a second document having a second document encoding, wherein the first document encoding and the second document encoding are different document encodings;

generating a second signature of data, wherein the data is included in the second document;

canonicalizing the first document from the first document encoding to a canonicalized first document having a canonical encoding, wherein canonicalizing the first document includes providing a different order of data within the first document based on a canonical ordering;

generating a third signature of data, wherein the data is included in the canonicalized first document; and

associating the first signature, the second signature, and the third signature with the first document to provide a digitally signed first document.

2. A computer implemented method as recited in claim 1, wherein the first signature, the second signature, and the third signature are transferred to a recipient.

3. A computer implemented method as recited in claim 1, wherein the first signature, the second signature, and the third signature are combined together to form a single multiple encoding signature.

4. A computer implemented method as recited in claim 3, wherein an order of the first signature, the second signature, and the third signature within a multiple encoding signature is predetermined.

5. A computer implemented method as recited in claim 1, wherein generating the first signature includes generating a signature for at least a portion of the data included in the first document.

6. A computer implemented method as recited in claim 1, wherein generating the first signature, the second signature, and the third signature includes generating a label associated with a hash.

7. A computer implemented method as recited in claim 6, wherein the label includes hash location, hash size, one or more encoding identifiers corresponding to one or more hashes, identifier identifying data corresponding to one or more hashes, and any hash attributes.

8. A computer implemented method as recited in claim 1, wherein the first signature, the second signature, and the third signature are included in a metadata of the first document.

9. A computer implemented method as recited in claim 1, wherein a data value corresponding to an order of the first signature, the second signature, and the third signature is included in a metadata of the first document.

10. A computer implemented method as recited in claim 1, wherein canonicalizing the first document includes canonicalizing at least a portion of the data of the first document.

11. A computer implemented method as recited in claim 1, wherein the first signature is a first encrypted hash, the second signature is a second encrypted hash, and the third signature is a third encrypted hash.

12. A computer implemented method as recited in claim 1, wherein the first signature, the second signature, and the third signature are each encrypted hashes, and wherein the first signature, the second signature, and the third signature are packaged together to form a multiple encoding signature.

13. A computer implemented method as recited in claim 1, wherein the one or more signatures are stored in a module separate from the digitally signed first document.

14. A computer implemented method as recited in claim 1, wherein the one or more signatures are stored in an order, including a hierarchical order.

15. A computer implemented method as recited in claim 1, wherein more than three signatures are generated.

16. A system comprising:

a processor configured to;

generate a first signature of data, wherein the data is included in a first document and wherein the first document has a first document encoding;

convert the first document from the first document encoding to a second document having a second document encoding, wherein the first document encoding and the second document encoding are different document encodings;

generate a second signature of data, wherein the data is included in the second document;

canonicalize the first document from the first document encoding to a canonicalized first document having a canonical encoding, wherein canonicalizing the first document includes providing a different order of data within the first document based on a canonical ordering;

generate a third signature of data, wherein the data is included in the canonicalized first document; and

associate the first signature, the second signature, and the third signature with the first document to provide a digitally signed first document; and

a memory coupled to the processor and configured to provide instructions to the processor.

17. A system as recited in claim 16, wherein the first signature, the second signature, and the third signature are combined together to form a single multiple encoding signature.

18. A system as recited in claim 16, wherein the processor is configured to generate the first signature, the second signature, and the third signature, including by generating a label associated with a hash.

19. A system as recited in claim 16, wherein the first signature, the second signature, and the third signature are each encrypted hashes, and wherein the first signature, the second signature, and the third signature are packaged together to form a multiple encoding signature.

20. A computer program product, the computer program product being embodied in a computer readable storage medium and comprising computer instructions for:

generating a first signature of data, wherein the data is included in a first document, and wherein the first document has a first document encoding;

converting the first document from the first document encoding to a second document having a second document encoding, wherein the first document encoding and the second document encoding are different document encodings;

generating a second signature of data, wherein the data is included in the second document;

canonicalizing the first document from the first document encoding to a canonicalized first document having a canonical encoding, wherein canonicalizing the first document includes providing a different order of data within the first document based on a canonical ordering;

generating a third signature of data, wherein the data is included in the canonicalized first document; and

associating the first signature, the second signature, and the third signature with the first document to provide a digitally signed first document.

21. A computer program product as recited in claim 20, wherein the first signature, the second signature, and the third signature are combined together to form a single multiple encoding signature.

22. A computer program product as recited in claim 20, wherein generating the first signature includes generating a label associated with a hash.

23. A computer program product as recited in claim 20, wherein the first signature, the second signature, and the third signature are each encrypted hashes, and wherein the first signature, the second signature, and the third signature are packaged together to form a multiple encoding signature.