Reversible Hashing for E-Signature Verification

• US 20080172560A1
• Filed: 01/15/2007
• Published: 07/17/2008
• Est. Priority Date: 01/15/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Hughes, Aidan T., Tankovich, Vladimir
• Granted Patent: US 7,882,358 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: H04L 2209/04 Masking or blinding
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

Embodiments of the present invention relate to systems and methods to authenticate software licenses. One embodiment of the present invention comprises a method where a vendor creates a reversible hash from a known, predetermined seed value, encrypts the hash to generate a digital signature, and sends the digital signature to the customer. The customer enters the digital signature. The customer'"'"'s client computer reverses the reversible hash to obtain a determined seed value. The client has access to the known seed value used by the vendor. The known seed value is compared to the determined seed value. If the seed values compare, the software license and the associated software is authenticate.

Claims

1. A computer readable medium, executable on a computing system, including at least one tangible medium and encoding a computer program of instructions for executing a computer implemented method for providing verification of a digital signature associated with a software license, the method comprising:

providing an original seed value;

providing a digital signature;

extracting a reversible hash value from the digital signature;

reversing the reversible hash to obtain a determined seed value;

comparing the determined seed value to the original seed value; and

if the determined seed value compares to the original seed value, verifying the signature and the associated software license.

2. The computer readable medium defined in claim 1, wherein the original seed value is known for both a client and a clearinghouse.

3. The computer readable medium defined in claim 1, wherein the original seed value is the same for all software of a same type, wherein the software is associated with the software license.

4. The computer readable medium defined in claim 1, wherein providing a digital signature comprises sending the digital signature from a clearinghouse to a client.

5. The computer readable medium defined in claim 1, wherein providing a digital signature comprises:

a vendor communicating the digital signature to a customer over a telephone; and

the customer entering the digital signature into a client.

6. The computer readable medium defined in claim 1, wherein extracting a hash reversible value from the digital signature comprises decrypting the digital signature to obtain the hash reversible value.

7. The computer readable medium defined in claim 1, wherein one or more counter functions are associated with and reverse one or more functions executed to create the reversible hash value.

8. The computer readable medium defined in claim 7, wherein the one or more functions are a modified MD5 algorithm executed twice, and wherein the counter functions reverse the MD5 algorithm.

9. The computer readable medium defined in claim 7, wherein both the one or more functions and the one or more counter functions use the same data as operands.

10. The computer readable medium defined in claim 7, wherein the associated one or more counter functions are executed in reverse order from the one or more functions.

11. The computer readable medium defined in claim 1, further comprising allowing installation of software associated with the software license.

12. A computer readable medium, executable on a computing system, including at least one tangible medium and encoding a computer program of instructions for executing a computer implemented method for providing a reversible digital signature associated with a software license, the method comprising:

receiving a seed value;

receiving at least one other item of information;

generating a reversible hash from a first function with the seed value as a first operand and at least one other item of information as the second operand, wherein the reversible hash is operable to be reversed at a client using a counter function that reverse the first function;

encrypting the reversible hash to create a digital signature; and

providing the digital signature to a client, wherein the client reverses the reversible hash to verify the software license.

13. The computer readable medium defined in claim 12, wherein the seed value is known for all software associated with the software license.

14. The computer readable medium defined in claim 13, wherein the seed value is read from a predetermined memory address in the software.

15. The computer readable medium defined in claim 12, wherein the at least one other item of information is one of a customer'"'"'s identity, a customer'"'"'s address, one or more descriptors of a computer used by a customer, a software package the customer wants to install, a time, a date, a store at which the customer purchased the software package, or a portion of software.

16. The computer readable medium defined in claim 12, wherein the reversible hash is created by a modified MD5 algorithm.

17. A system for verifying a digital signature associated with a software license, the system comprising:

a reverse hash algorithm component, the reverse hash algorithm component operable to receive a reversible hash, to execute one or more counter functions operating on data from one of a data packet, a software, or a known seed value to extract a determined seed value from the reversible hash;

a compare seed value component in electrical communication with the reverse hash algorithm component, the compare seed value component operable to receive the determined seed value, to receive the known seed value, to compare the determined seed value to the known seed value, and to verify authenticity of the software license if the determined seed value compares to the known seed value.

18. The system defined in claim 17, further comprising:

a decryption engine in electrical communication with the reverse hash algorithm component, the decryption engine operable to receive a digital signature, to decrypt the digital signature to extract the reversible hash, and to provide the reversible hash to the reverse hash algorithm component.

19. The system defined in claim 17, further comprising a clearinghouse in electrical communication with the reverse hash algorithm component, wherein the clearinghouse comprises:

a hash algorithm component, the hash algorithm component operable to execute one or more functions to generate the reversible hash from the known seed value and the data from one of the data packet or the software and to provide the reversible hash.

20. The system defined in claim 19, wherein the hash algorithm component and the reverse hash algorithm component execute a same number of functions, wherein the counter functions executed by the reverse hash algorithm component reverse the functions executed by hash algorithm component, and wherein the counter functions are executed in reverse order from the functions executed by the hash algorithm component.