SECURE OFFLINE ACTIVATION PROCESS FOR LICENSED SOFTWARE APPLICATION PROGRAMS

• US 20080301447A1
• Filed: 06/01/2007
• Published: 12/04/2008
• Est. Priority Date: 06/01/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Hughes, Aidan, de la Torre, Douglas R.
• Granted Patent: US 8,392,713 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: H04L 2209/04 Masking or blinding
• CPC Class Codes: H04L 2209/20 Manipulating the length of blocks of bits, e.g. padding or block truncation
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

A computer readable medium for activating a software application for execution on a designated computer, where the computer readable medium has stored thereon computer executable instructions for performing the following steps: computing an installation identifier reflective of the software application and the designated computer; receiving an activation code generated in accordance with the installation identifier and a blinding factor value; computing a first verification code as a function of the installation identifier; computing a trial blinding factor value; computing a decryption key as a function of the trial blinding factor value and the activation code; using the decryption key to decrypt a second verification code; verifying that the first verification code matches the second verification code; and, activating the software application for execution on the designated computer.

Claims

1. A computer readable medium for activating a software application for execution on a designated computer, the computer readable medium having stored thereon computer executable instructions for performing the following steps:

(a) computing an installation identifier representative of the software application and the designated computer;

(b) receiving an activation code generated in accordance with the installation identifier and a blinding factor value;

(c) computing a reference value as a function of the installation identifier;

(d) computing a decryption key as a function of the activation code and a trial blinding factor value;

(e) using the decryption key to access an encrypted value representative of the installation identifier; and

,

(f) comparing the encrypted value to the reference value.

2. The computer readable medium of claim 1, wherein the reference value and the encrypted value are computed based a hash of the installation identifier.

3. The computer readable medium of claim 1, wherein the computer executable instructions are further for performing the step of translating the installation identifier to a specified format suitable for transmission over a low bandwidth medium.

4. The computer readable medium of claim 1, wherein the decryption key computing step further comprises:

(a) applying a specified hash algorithm to the activation code and the blinding factor a specified number of iterations to obtain a desired hash value; and

,

(b) truncating the desired hash value to a specified length.

5. The computer readable medium of claim 1, wherein the computer executable instructions are further for performing the step of receiving the activation code from an offline remote server.

6. The computer readable medium of claim 1, wherein the reference value and the encrypted value are computed based on a memory intensive operation.

7. The computer readable medium of claim 1, wherein the computer executable instructions are further for performing the step of activating the software application for execution on the designated computer when the encrypted value matches the reference value.

8. The computer readable medium of claim 7, wherein the computer executable instructions are further for performing the step of recording information relating to activation of the software application.

9. The computer readable medium of claim 1, wherein the computer executable instructions are further for performing the following steps:

(a) utilizing a new trial blinding factor value with the activation code when the encrypted value does not match the reference hash value; and

,

(b) computing a new decryption key as a function of the activation code and the new trial blinding factor value.

10. The computer readable medium of claim 3, wherein the translated installation identifier is a digit string having a specified number of digits.

11. A computer readable medium for activating a software application for execution on a designated computer, the computer readable medium having stored thereon computer executable instructions for performing the following steps:

(a) receiving an installation identifier representative of the software application and the designated computer;

(b) computing a blinding factor;

(c) identifying a digital signature corresponding to the installation identifier; and

,

(d) computing an activation code such that the digital signature is a function of the activation code and the blinding factor.

12. The computer readable medium of claim 11, wherein the computer executable instructions are further for performing the step of confirming the validity of the installation identifier.

13. The computer readable medium of claim 12, wherein the computer executable instructions are further for performing the step of recording activation of the software application.

14. The computer readable medium of claim 11, wherein the computer executable instructions are further for performing the step of applying a hash algorithm to the activation code and the blinding factor.

15. The computer readable medium of claim 14, wherein the computer executable instructions are further for performing the step of translating the hash value of the activation code and the blinding factor to a specified format.

16. The computer readable medium of claim 15, wherein the translated hash value of the activation code and the blinding factor is a digit string having a specified number of digits.

17. The computer readable medium of claim 15, wherein the computer executable instructions are further for performing the step of transmitting the activation code to the designated computer via an offline medium.

18. A method of activating a software application offline for execution on a designated computer, comprising the following steps:

(a) computing an installation identifier representative of the software application and the designated computer;

(b) receiving an activation code generated in accordance with the installation identifier and a blinding factor value;

(c) computing a reference value as a function of the installation identifier;

(e) computing a decryption key as a function of the activation code and a trial blinding factor value;

(f) using the decryption key to access an encrypted value representative of the installation identifier; and

(f) comparing the encrypted value to the reference value.

19. The method of claim 18, further comprising activating the software application for execution on the designated computer when the encrypted value matches the reference value.

20. The method of claim 18, further comprising:

(a) utilizing a new trial blinding factor value with the activation code when the encrypted value does not match the reference value; and

,

(b) computing a new decryption key as a function of the activation code and the new trial blinding factor value.