SYSTEM AND METHOD FOR OBFUSCATION INITIATION VALUES OF A CRYPTOGRAPHY PROTOCOL

• US 20130024697A1
• Filed: 07/22/2011
• Published: 01/24/2013
• Est. Priority Date: 07/22/2011
• Status: Active Grant

• Current Assignee: Netflix, Inc.
• Original Assignee: Netflix, Inc.
• Inventors: Zollinger, Mitch, Paun, Filip
• Granted Patent: US 8,782,420 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: H04L 2209/605 Copy protection
• CPC Class Codes: H04L 63/0414 during transmission, i.e. party's identity is protected against eavesdropping, e.g. by using temporary identifiers, but is known to the other party or parties involved in the communication
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04L 9/3271 using challenge-response

Abstract

A computer-implemented technique for determining whether a first computing device has the correct version of a software program may be used to provide a secure approach to verifying that a client computing device has a secure and approved version of content player software implemented for consuming downloaded copyright media content. With this technique, copyright media content providers are able to ensure that only secure and approved content players are implemented to access the content.

Claims

1. A computer-implemented method for determining whether a first computing device has the correct version of a software program, the method comprising:

computing a private secret value based on at least one initial setup value;

computing a public value based on the private secret value and at least one initial setup value;

sending the public value to the second computing device;

receiving a second public value from the second computing device;

computing a shared secret based on the second public value received from the second computing device and the private secret value;

receiving an encrypted message from the second computing device;

decrypting the encrypted message using the shared secret;

determining whether the message was decrypted correctly; and

if the message was decrypted correctly, causing communications between the first computing device and the second computing device to continue because the first computing device and the second computing device have the same version of the software program;

or

if the message was not decrypted correctly, causing communications between the first computing device and the second computing device to terminate because the first computing device and the second computing device do not have the same version of the software program.

2. The method of claim 1, wherein the cryptography algorithm used to encrypt and decrypt the message comprises a Diffie-Hellman key exchange algorithm, an ElGamal encryption algorithm or a digital signature algorithm.

3. The method of claim 1, wherein the at least one initial setup value comprises a base generator value or a prime element value.

4. The method of claim 3, wherein a binary representation of the base generator value is comprised of more bits than a first threshold number and has less than a second threshold number of 1 bits.

5. The method of claim 3, wherein a binary representation of the prime element value is comprised of more bits than a third threshold number.

6. The method of claim 1, wherein the encrypted message comprises an original message encrypted based on a shared secret computed by the second computing device.

7. The method of claim 6, wherein, if the message is decrypted correctly, then the decrypted message matches the original message, and the shared secret computed based on the second public value received from the second computing device is equal to the shared secret computed by the second computing device.

8. The method of claim 1, wherein the second computing device determines whether the message was decrypted correctly and causes communications between the first computing device and the second computing device to continue or terminate.

9. The method of claim 1, wherein the computation of the private secret value, the public value and the shared secret by the first computing device is obfuscated.

10. The method of claim 1, wherein the software program comprises a content player application for receiving and displaying video data.

11. A non-transitory computer-readable medium storing instructions that, when executed by a processing unit, cause the processing unit to determine whether a first computing device has the correct version of a software program, by performing the steps of:

computing a private secret value based on at least one initial setup value;

computing a public value based on the private secret value and at least one initial setup value;

sending the public value to the second computing device;

receiving a second public value from the second computing device;

computing a shared secret based on the second public value received from the second computing device and the private secret value;

receiving an encrypted message from the second computing device;

decrypting the encrypted message using the shared secret; and

determining whether the message was decrypted correctly, wherein

if the message was decrypted correctly, then communications between the first computing device and the second computing device continue because the first computing device and the second computing device have the same version of the software program;

or

if the message was not decrypted correctly, then communications between the first computing device and the second computing device terminate because the first computing device and the second computing device do not have the same version of the software program.

12. The computer-readable medium of claim 11, wherein the cryptography algorithm used to encrypt and decrypt the message comprises a Diffie-Hellman key exchange algorithm, an ElGamal encryption algorithm or a digital signature algorithm.

13. The computer-readable medium of claim 11, wherein the at least one initial setup value comprises a base generator value or a prime element value.

14. The computer-readable medium of claim 13, wherein a binary representation of the base generator value is comprised of more bits than a first threshold number and has less than a second threshold number of 1 bits.

15. The computer-readable medium of claim 13, wherein a binary representation of the prime element value is comprised of more bits than a third threshold number.

16. The computer-readable medium of claim 11, wherein the encrypted message comprises an original message encrypted based on a shared secret computed by the second computing device.

17. The computer-readable medium of claim 16, wherein, if the message is decrypted correctly, then the decrypted message matches the original message, and the shared secret computed based on the second public value received from the second computing device is equal to the shared secret computed by the second computing device.

18. The computer-readable medium of claim 11, wherein the second computing device determines whether the message was decrypted correctly and causes communications between the first computing device and the second computing device to continue or terminate.

19. The computer-readable medium of claim 11, wherein the computation of the private secret value, the public value and the shared secret by the first computing device is obfuscated.

20. A first computing device, comprising:

a processing unit configured to;

compute a private secret value based on at least one initial setup value;

compute a public value based on the private secret value and on at least one initial setup value;

send the public value to the second computing device;

receive a second public value from the second computing device;

compute a shared secret based on the second public value received from the second computing device and the private secret value;

receive an encrypted message from the second computing device;

decrypt the encrypted message using the shared secret; and

determine whether the message was decrypted correctly, wherein

if the message was decrypted correctly, then communications between the first computing device and the second computing device continue because the first computing device has the correct version of a software program, or

if the message was not decrypted correctly, then communications between the first computing device and the second computing device terminate because the first computing device does not have the correct version of the software program