Securely recovering a computing device

Patent metadata

Field	Value
Publication number	US-9680648-B2
Application number	US-201615077794-A
Country	US
Kind code	B2
Filing date	Mar 22, 2016
Priority date	Jan 7, 2007
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A method and an apparatus for establishing an operating environment by certifying a code image received from a host over a communication link are described. The code image may be digitally signed through a central authority server. Certification of the code image may be determined by a fingerprint embedded within a secure storage area such as a read only memory (ROM) of the portable device based on a public key certification process. A certified code image may be assigned a hash signature to be stored in a storage of the portable device. An operating environment of the portable device may be established after executing the certified code.

First claim

What is claimed is:

1. A method carried out at a computing device, the method comprising:
loading, into a storage of the computing device, a code image that is digitally signed by a signature;
determining whether the code image is certified by verifying the signature using a fingerprint embedded within a read only memory (ROM) of the computing device;
when the code image is certified:
executing the code image to establish an operating environment of the computing device; and

when the code image is not certified:
removing the code image from the storage of the computing device, and
entering a Device Firmware Upgrade (DFU) mode to perform system management tasks for the computing device.

2. The method of claim 1 , wherein the fingerprint is associated with a unique identifier (UID) specific to the computing device.

3. The method of claim 1 , wherein executing the code image comprises:
determining whether the code image matches the signature based on a public key compatible with X.509 standard; and
determining whether the fingerprint matches the public key, wherein the fingerprint is based on a first hash value of the public key.

4. The method of claim 3 , further comprising:
deriving a second hash value based on the code image; and
encrypting the second hash value into a header value based on a key stored in the ROM of the computing device.

5. The method of claim 1 , further comprising, when the code image is certified:
verifying that an operating system component is trusted before executing the operating system component in the storage.

6. The method of claim 1 , wherein the code image is received from an entity that is communication with the computing device.

7. The method of claim 1 , further comprising:
resetting the computing device.

8. A non-transitory computer readable storage medium configured to store instructions that, when executed by a processor included in a computing device, cause the computing device to carry out steps that include:
loading, into a storage of the computing device, a code image that is digitally signed by a signature;
determining whether the code image is certified by verifying the signature using a fingerprint embedded within a read only memory (ROM) of the computing device;
when the code image is certified:
executing the code image to establish an operating environment of the computing device; and

when the code image is not certified:
removing the code image from the storage of the computing device, and
entering a Device Firmware Upgrade (DFU) mode to perform system management tasks for the computing device.

9. The non-transitory computer readable storage medium of claim 8 , wherein the fingerprint is associated with a unique identifier (UID) specific to the computing device.

10. The non-transitory computer readable storage medium of claim 8 , wherein executing the code image comprises:
determining whether the code image matches the signature based on a public key compatible with X.509 standard; and
determining whether the fingerprint matches the public key, wherein the fingerprint is based on a first hash value of the public key.

11. The non-transitory computer readable storage medium of claim 10 , wherein the steps further include:
deriving a second hash value based on the code image; and
encrypting the second hash value into a header value based on a key stored in the ROM of the computing device.

12. The non-transitory computer readable storage medium of claim 8 , wherein the steps further include, when the code image is certified:
verifying that an operating system component is trusted before executing the operating system component in the storage.

13. The non-transitory computer readable storage medium of claim 8 , wherein the code image is received from an entity that is communication with the computing device.

14. The non-transitory computer readable storage medium of claim 8 , wherein the steps further include:
resetting the computing device.

15. A computing device comprising a processor configured to cause the computing device to carry out steps that include:
loading, into a storage of the computing device, a code image that is digitally signed by a signature;
determining whether the code image is certified by verifying the signature using a fingerprint embedded within a read only memory (ROM) of the computing device;
when the code image is certified:
executing the code image to establish an operating environment of the computing device; and

when the code image is not certified:
removing the code image from the storage of the computing device, and
entering a Device Firmware Upgrade (DFU) mode to perform system management tasks for the computing device.

16. The computing device of claim 15 , wherein the fingerprint is associated with a unique identifier (UID) specific to the computing device.

17. The computing device of claim 15 , wherein executing the code image comprises:
determining whether the code image matches the signature based on a public key compatible with X.509 standard; and
determining whether the fingerprint matches the public key, wherein the fingerprint is based on a first hash value of the public key.

18. The computing device of claim 17 , wherein the steps further include:
deriving a second hash value based on the code image; and
encrypting the second hash value into a header value based on a key stored in the ROM of the computing device.

19. The computing device of claim 15 , wherein the steps further include, when the code image is certified:
verifying that an operating system component is trusted before executing the operating system component in the storage.

20. The computing device of claim 15 , wherein the code image is received from an entity that is communication with the computing device.

Assignees

• Apple Inc

Inventors

• De Atley Dallas Blake
• De Cesare Joshua
• Smith Michael
• Reda Matthew
• Sen Shantonu
• Wright John Andrew

Classifications

• G06F21/64

  Protecting data integrity, e.g. using checksums, certificates or signatures · CPC title

• H04L9/302 Primary

  involving the integer factorization problem, e.g. RSA or quadratic sieve [QS] schemes · CPC title

• H04L9/14

  using a plurality of keys or algorithms · CPC title

• H04L9/3249

  using RSA or related signature schemes, e.g. Rabin scheme · CPC title

• H04L63/06

  for supporting key management in a packet data network (cryptographic mechanisms or cryptographic arrangements for key management H04L9/08) · CPC title