Tamper evidence per device protected identity

Patent metadata

Field	Value
Publication number	US-9647847-B2
Application number	US-201614991262-A
Country	US
Kind code	B2
Filing date	Jan 8, 2016
Priority date	Jan 18, 2008
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

Various techniques are described to protect secrets held by closed computing devices. In an ecosystem where devices operate and are offered a wide range of services from a service provider, the service provider may want to prevent users from sharing services between devices. In order to guarantee that services are not shared between devices, each device can be manufactured with a different set of secrets such as per device identifiers. Unscrupulous individuals may try to gain access to the secrets and transfer secrets from one device to another. In order to prevent this type of attack, each closed computing system can be manufactured to include a protected memory location that is tied to the device.

First claim

What is claimed is:

1. A computing device, comprising:
a processer;
a one-time writable storage device including a device specific number permanently fixed therein; and
a storage medium coupled to the processor, the storage medium including a protected memory location that contains content, wherein the content of the protected memory location includes a device identifier and a plurality of asymmetric service keys used to access at least one or more services;
the storage medium including executable instructions that upon execution:
generate a digital signature by encrypting a hash of the content in the protected memory location and the permanently fixed device specific number by using one of the plurality of asymmetric service keys used by a manufacture of the computing device; and
store the digital signature in the protected memory location.

2. The computing device of claim 1 , wherein the protected memory location is encrypted using the permanently fixed device specific number.

3. The computing device of claim 1 , wherein the one-time writable storage device is associated with or a part of the processor.

4. The computing device of claim 3 , wherein the device specific number is permanently fixed in the one-time writable storage device by at least one of: burning, etching, and affixing the device specific number inside the processor of the one-time writable storage device.

5. The computing device of claim 1 , wherein the device identifier is used to identify the computing device to a service provider.

6. A method for manufacturing a computing device, comprising:
storing, during a manufacturing of a device, content in a protected memory location effectuated by non-volatile storage of the device,
wherein the content includes a device identifier and a plurality of asymmetric service keys used to access at least one or more services;

affixing, during the manufacturing of the device, a permanent device specific number for the device into one-time writable storage in the device;
generating, during the manufacturing of the device, a hash based on the content in the protected memory location of the device and the permanent device specific number;
encrypting, during the manufacturing of the device, the hash using one of the plurality of asymmetric service keys; and
storing the encrypted hash in the protected memory location.

7. The method of claim 6 , wherein the one-time writable storage is associated with or a part of the processor of the device.

8. The method of claim 7 , wherein affixing the permanent device specific number further comprises:
etching the permanent device specific number inside the processor of the device using the one-time writable storage.

9. The method of claim 7 , wherein affixing the permanent device specific number further comprises:
burning the permanent device specific number inside the processor of the device using the one-time writable storage.

10. The method of claim 6 , wherein the permanent device specific number is a symmetric key.

11. The method of claim 10 , further comprising:
encrypting the protected memory location using the symmetric key.

12. A computer-readable storage device including executable instructions that upon execution cause a processor to perform instructions comprising:
reading a current permanent device specific number affixed in a one-time writable storage;
calculating a current hash value based on current content in a non-volatile protected memory location of the device and based on the current permanent device specific number, wherein the current content includes a deceive identifier and a plurality of asymmetric service keys used to access at least one or more services;
decrypting a digital signature, wherein the digital signature contains a prior hash value calculated from prior content in the non-volatile protected memory location and a prior device specific number;
comparing the current hash value to the prior hash value; and
retrieving a secret from the non-volatile protected memory location when the current hash value is equal to the prior hash value.

13. The computer-readable storage device of claim 12 , the instructions further comprising:
performing a pre-determined action in response to determining that the device has been tampered with when the current hash value is not equal to the prior hash value.

14. The computer-readable storage device of claim 13 , wherein performing a pre-determined action further comprising:
preventing the sharing of services, by a service provider, between the device and at least one other device.

15. The computer-readable storage device of claim 13 , wherein performing a pre-determined action further comprising:
shutting down the device.

16. The computer-readable storage device of claim 13 , wherein performing a pre-determined action further comprising:
informing the service provider that the device has been compromised.

17. The computer-readable storage device of claim 12 , wherein the digital signature is embedded in the non-volatile protected memory location.

18. The computer-readable storage device of claim 17 , the instructions further comprising:
decrypting the current content of the protected memory location using the affixed permanent device specific number.

19. The computer-readable storage device of claim 12 , the instructions further comprising:
receiving a data package;
calculating a hash of the data package;
encrypting the hash using at least one of the asymmetric service keys;
transmitting the encrypted hash to a service provider; and
receiving media from the service provider.

20. The computer-readable storage device of claim 12 , wherein the prior hash value is calculated from prior content in the protected memory location and a prior device specific number.

Assignees

• Microsoft Technology Licensing Llc

Inventors

• Lange Sebastian
• Tan Victor
• Poulos Adam G

Classifications

• H04N21/4623

  Processing of entitlement messages, e.g. ECM [Entitlement Control Message] or EMM [Entitlement Management Message] {(arrangements for conditional access to broadcast information or to broadcast-related services H04H60/14)} · CPC title

• H04W12/08

  Access security · CPC title

• H04W12/06

  Authentication · CPC title

• H04N7/165

  Centralised control of user terminal (subsequent to an upstream request signal H04N7/17345); Registering at central (by two-way working H04N7/17309) · CPC title

• G06F21/6218 Primary

  to a system of files or objects, e.g. local or distributed file system or database · CPC title