Secure offline activation process for licensed software application programs
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.
1. A computer readable storage medium that is not a signal and that is for activating a software application for execution on a designated computer, the computer readable storage 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, the activation code obtained using an offline medium;
(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, the computing of the decryption key comprising:
applying a specified hash algorithm to the activation code and the trial blinding factor a specified number of iterations to obtain a resulting hash value; and
truncating the resulting hash value to a specified length;
(e) using the decryption key to access an encrypted value representative of the installation identifier;
(f) comparing the encrypted value to the reference value
(g) utilizing a new trial blinding factor value with the activation code when the encrypted value does not match the reference hash value; and
(h) computing a new decryption key as a function of the activation code and the new trial blinding factor value.
2. The computer readable storage medium of claim 1 , wherein the reference value and the encrypted value are computed based on a hash of the installation identifier.
3. The computer readable storage 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 storage medium of claim 3 , wherein the translated installation identifier is a digit string having a specified number of digits.
5. The computer readable storage medium of claim 1 , wherein the reference value and the encrypted value are computed based on a memory intensive operation.
6. The computer readable storage 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.
7. The computer readable storage medium of claim 6 , wherein the computer executable instructions are further for performing the step of recording information relating to activation of the software application.
8. A method of activating a software application 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, the activation code obtained using an offline medium;
(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, the computing of the decryption key comprising:
applying a specified hash algorithm to the activation code and the trial blinding factor a specified number of iterations to obtain a resulting hash value; and
truncating the resulting hash value to a specified length;
(e) using the decryption key to access an encrypted value representative of the installation identifier;
(f) comparing the encrypted value to the reference value
(g) utilizing a new trial blinding factor value with the activation code when the encrypted value does not match the reference value; and
(h) computing a new decryption key as a function of the activation code and the new trial blinding factor value.
9. The method of claim 8 , further comprising activating the software application for execution on the designated computer when the encrypted value matches the reference value.
10. The method of claim 9 , further comprising recording information relating to activation of the software application.
11. The method of claim 8 , wherein the reference value and the encrypted value are computed based on a hash of the installation identifier.
12. The method of claim 8 , further comprising translating the installation identifier to a specified format suitable for transmission over a low bandwidth medium.
13. The method of claim 12 , wherein the translated installation identifier is a digit string having a specified number of digits.
14. The method of claim 8 , wherein the reference value and the encrypted value are computed based on a memory intensive operation.