Establishing a secure communication session with an external security processor

Patent metadata

Field	Value
Publication number	US-11601409-B2
Application number	US-201816212054-A
Country	US
Kind code	B2
Filing date	Dec 6, 2018
Priority date	Sep 30, 2010
Publication date	Mar 7, 2023
Grant date	Mar 7, 2023

Abstract

A security system is disclosed in which a secure communication session is established between an external security processor and an interface device. After insertion of the external security processor into the interface device, an authorization server provides authorization to the external security processor and the interface device based on, for example, identification information for each device. A derived key may be generated using a common device security key, and a seed value stored at the interface device. The derived key may then be used for multiple communication sessions between the interface device and the external security processor.

First claim

The invention claimed is:

1. A method comprising:
after insertion of an external security processor device into an interface device, obtaining first identification information from the external security processor device and second identification information from the interface device;
sending the first identification information and the second identification information to a server of a service provider;
receiving, based on the first identification information and the second identification information, authorization from the server of the service provider;
establishing, based on the authorization, a secure session between the external security processor device and the interface device, wherein establishing the secure session comprises creating a session key;
retrieving a device security key via the interface device;
encrypting the device security key using a first seed value to derive a first derived key;
encrypting the first derived key with the session key;
storing the encrypted first derived key in a first storage area of the interface device;
sending the encrypted first derived key to the external security processor device;
after a compromise of the first derived key, re-encrypting the device security key using a second seed value to derive a second derived key; and
storing the second derived key in a second storage area of the interface device.

2. The method of claim 1 , wherein the first identification information comprises at least one of a serial number or a media access control (MAC) address of the external security processor device.

3. The method of claim 1 , wherein the second identification information comprises one or more of information identifying a security module of the interface device or information identifying a security platform processor of the interface device.

4. The method of claim 1 , wherein establishing a secure session comprises creating a session key using a Diffie-Hellman key exchange.

5. The method of claim 1 , further comprising sending a report of a pairing between the external security processor device and the interface device to the service provider, and dissolving the pairing after the compromise of the first derived key.

6. The method of claim 1 ,
wherein the first storage area and second storage area are physically separate memories.

7. A method comprising:
after insertion of an external security processor device into a video interface device, obtaining first identification information from the external security processor device and second identification information from the video interface device;
sending the first identification information and the second identification information to a server of a service provider;
receiving, based on the first identification information and the second identification information, authorization from the server of the service provider; and
performing, by a computing device and to derive a first derived key, a first encryption using:
a device security key stored in a first memory storage area of the computing device; and
a first seed value;

storing the first derived key in a second memory storage area of the computing device;
establishing, based on the authorization, a secure communication session between the computing device and an external security processor;
using the secure communication session to send the first derived key to the external security processor;
performing, after a compromise of the first derived key, a second encryption using the device security key;
deriving, using a second seed value comprising a combination of an address of the computing device and a second random number, a second derived key; and
storing the second derived key in the second memory storage area of the computing device.

8. The method of claim 7 , further comprising:
terminating the secure communication session after the compromise of the first derived key; and
using, by a replacement external security processor, the second derived key.

9. The method of claim 7 , further comprising:
sending a report of a pairing between the external security processor device and the video interface device to the server of the service provider; and
dissolving the pairing after a compromise of the first derived key.

10. The method of claim 7 wherein the first seed value comprises a combination of an address of the video interface device and a random number.

11. The method of claim 7 , wherein:
the device security key is common to a plurality of other devices; and
the second derived key is derived after a global compromise of the first derived key.

12. The method of claim 7 , further comprising:
receiving, after the compromise of the first derived key, an instruction to encrypt the device security key a second time;
performing, based on the instruction, the second encryption using the device security key, wherein:
the device security key is common to a plurality of other devices; and
the second derived key is derived after a global compromise of the first derived key.

13. A method comprising:
after insertion of an external security processor device into an interface device of a plurality of different devices, obtaining first identification information from the external security processor device and second identification information from the interface device;
sending the first identification information and the second identification information to a server of a service provider;
receiving, based on the first identification information and the second identification information, authorization from the server of the service provider;
encrypting, by a processor, using a first seed value, and to create a first derived key for the interface device, a device security key stored in a first memory storage area of a computing device of the interface device, wherein the device security key is common to the plurality of different devices;
using the first derived key for multiple communication sessions via the interface device;
determining that a compromise of the first derived key has occurred;
determining a subset of the plurality of different devices affected by the compromise; and
receiving, via the processor, an instruction to perform, based on a second seed, and to derive a second derived key for the interface device, a second encryption of the device security key, wherein the second encryption of the device security key produces a second derived key for the subset of the plurality of different devices, and the second derived key is different from the first derived key.

14. The method of claim 13 , further comprising:
splintering the subset of the plurality of different devices into two or more smaller subsets after a second key compromise; and
instructing one of the smaller subsets to produce a third derived key for the one of the smaller subsets.

15. The method of claim 13 , further comprising:
sending a report of a pairing between the external security processor device and the interface device to the server of the service provider; and
dissolving the pairing after a compromise of the first derived key.

16. The method of claim 13 , further comprising limiting use of the second derived key to the interface device.

17. The method of claim 13 , further comprising limiting use of the second derived key to an authorized pair of devices comprising the interface device and a second device.

Assignees

• Comcast Cable Comm Llc

Inventors

• Fahmy James W
• Kuykendall Pete
• Davoust Nancy

Classifications

• G11B20/0021

  involving encryption or decryption of contents recorded on or reproduced from a record carrier · CPC title

• H04L2463/101

  applying security measures for digital rights management · CPC title

• H04L9/30

  Public key, i.e. encryption algorithm being computationally infeasible to invert or user's encryption keys not requiring secrecy · CPC title

• G11B20/00478

  wherein contents are decrypted and re-encrypted with a different key when being copied from/to a record carrier · CPC title

• H04L63/068

  using time-dependent keys, e.g. periodically changing keys (cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088) · CPC title