Post-signing modification of software

• US 20060184798A1
• Filed: 02/16/2006
• Published: 08/17/2006
• Est. Priority Date: 02/17/2005
• Status: Active Grant

• Current Assignee: CA, Inc. (d/b/a CA Technologies) (Broadcom, Inc.)
• Original Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Inventors: Witmann, Jerome, Yaldwyn, Ben Francis
• Granted Patent: US 8,356,295 B2
• Time in Patent Office: Days
• US Class Current: 713/180
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/16 Program or content traceability, e.g. by watermarking
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures

Abstract

A technique for making post-signing modifications to a digitally-signed software application without invalidating the signature can be used to enhance a user experience when downloading the software application. An extension module extends the length of a signature section at the end of an executable file for the digitally-signed software application to form a storage section. A header adjustment module adjusts the header to indicate size of the storage section appended at the end of the executable file. A data insertion module inserts post-signing data into the storage section, and the validity of the digital signature is maintained without requiring the file to be re-signed after insertion of the post-signing data. Thus, a software vendor can add into the software user-specific data after the file has been signed, while still maintaining the signature'"'"'s validity, so the software can be downloaded with minimal interruption to the user.

Claims

1. A computer program product having a computer-readable medium having computer program instructions recorded thereon for making a post-signing modification to a digitally-signed software application to be downloaded by a user onto a computer, the computer program instruction comprising instructions for:

extending length of a signature section at an end of an executable file of the digitally-signed software application to form a storage section at an end of the signature section, wherein the executable file includes a digital signature in the signature section and a header describing sections of the executable file;

adjusting the header to indicate size of the storage section appended at the end of the executable file; and

inserting post-signing data into the storage section, wherein validity of the digital signature is maintained without requiring the file to be re-signed after insertion of the post-signing data.

2. The computer program product of claim 1, wherein the post-signing data is user-specific data that allows the user to install the digitally-signed software application on the computer with minimal user intervention.

3. The computer program product of claim 1, wherein adjusting the header further comprises adjusting size of a security directory entry within the header to accommodate the size of the storage section.

4. The computer program product of claim 1, wherein the digital signature is used by the computer for validating authenticity of the digitally-signed software application downloaded by the user from a website and wherein the post-signing data assists the user in installing the digitally-signed software application.

5. The computer program product of claim 1, further comprising creating the executable file, wherein the executable file is digitally signed to form the signature section of the executable file.

6. The computer program product of claim 1, wherein the extending length of a signature section to form the storage section further comprises extending size of the signature section in a header directory of a signature section header.

7. A method of making a post-signing modification to a digitally-signed software application to be downloaded by a user onto a computer, the method comprising:

extending length of a signature section at an end of an executable file of the digitally-signed software application to form a storage section at an end of the signature section, wherein the executable file includes a digital signature in the signature section and a header describing sections of the executable file;

adjusting the header to indicate size of the storage section appended at the end of the executable file; and

inserting post-signing data into the storage section, wherein validity of the digital signature is maintained without requiring the file to be re-signed after insertion of the post-signing data.

8. The method of claim 7, wherein adjusting the header further comprises adjusting size of a security directory entry within the header to accommodate the size of the storage section.

9. The method of claim 7, wherein the digital signature is used by the computer for validating authenticity of the digitally-signed software application downloaded by the user from a website and wherein the post-signing data assists the user in installing the digitally-signed software application.

10. The method of claim 7, further comprising creating the executable file, wherein the executable file is digitally signed to form the signature section of the file.

11. The method of claim 7, wherein extending length of a signature section to form the storage section further comprises extending size of the signature section in a header directory of a signature section header.

12. The method of claim 7, wherein inserting post-signing data further comprises storing a unique fingerprint for the user'"'"'s computer in the storage section.

13. A system for making a post-signing modification to a digitally-signed software application to be downloaded by a user onto a computer, the system comprising:

an extension module for extending length of a signature section at an end of an executable file of the digitally-signed software application to form a storage section at an end of the signature section, wherein the executable file includes a digital signature in the signature section and a header describing sections of the executable file;

a header adjustment module for adjusting the header to indicate size of the storage section appended at the end of the executable file; and

a data insertion module for inserting post-signing data into the storage section, wherein validity of the digital signature is maintained without requiring the file to be re-signed after insertion of the post-signing data.

14. The system of claim 13, wherein the header adjustment module is further adapted for modifying size of a security directory entry of the header to accommodate the size of the storage section.

15. The system of claim 13, further comprising a file creation module for creating the executable file, wherein the executable file is digitally signed to form the signature section of the file.

16. The system of claim 13, wherein the extension module is further adapted for extending size of the signature section in a header directory of a signature section header.

17. The system of claim 13, wherein the post-signing data is user-specific data collected by a software vendor that allows the user to install the digitally-signed software application on the computer.

18. The system of claim 13, wherein the post-signing data is selected from a group consisting of:

activation information and language text strings.

19. A system for making a post-signing modification to a digitally-signed software application to be downloaded by a user onto a computer, the system comprising:

means for extending length of a signature section at an end of an executable file of the digitally-signed software application to form a storage section at an end of the signature section, wherein the executable file includes a digital signature in the signature section and a header describing sections of the executable file;

means for adjusting the header to indicate size of the storage section appended at the end of the executable file; and

means for inserting post-signing data into the storage section, wherein validity of the digital signature is maintained without requiring the file to be re-signed after insertion of the post-signing data.

20. The system of claim 19, wherein the means for adjusting the header is further adapted for modifying size of a security directory entry of the header to accommodate the size of the storage section.