APPARATUS AND METHOD FOR MULTI-STATE CODE SIGNING

• US 20160127133A1
• Filed: 10/30/2014
• Published: 05/05/2016
• Est. Priority Date: 10/30/2014
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: PINDER, ELLIS A., MESSERGES, THOMAS S.
• Granted Patent: US 9,843,451 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 21/1011 to devices
• CPC Class Codes: G06F 21/121 Restricting unauthorised execution of programs
• CPC Class Codes: G06F 21/51 at application loading time, e.g. accepting, rejecting, starting or inhibiting executable software based on integrity or source reliability
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/126 the source of the received data
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB
• CPC Class Codes: H04L 9/3234 involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token network architectures or network communication protocols for supporting authentication of entities using an additional device in a packet data network H04L63/0853
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/3265 using certificate chains, trees or paths; Hierarchical trust model
• CPC Class Codes: H04L 9/3268 using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]

Abstract

An electronic device includes a memory configured to store a lab certificate, a code authentication certificate and the executable code. The electronic device also includes a processor associated with a unique device identifier. For a first operational condition of the plurality of operational conditions, the processor is configured to: retrieve the code authentication certificate associated with the executable code; determine that a valid lab certificate is present in the memory; authenticate the code authentication certificate by determining that the code authentication certificate is signed with a private developer key and that the signature is valid; and execute the executable code on the electronic device responsive to determining that the lab certificate is valid and authenticating the code authentication certificate.

Claims

1. An electronic device, comprising:

a memory configured to store a lab certificate, a code authentication certificate and an executable code; and

a processor associated with a unique device identifier, wherein, for a first operational condition of a plurality of operational conditions, the processor is configured to;

retrieve the code authentication certificate associated with the executable code;

determine that a valid lab certificate is present in the memory;

authenticate the code authentication certificate by determining that the code authentication certificate is signed with a private developer key and that the signature is valid, and

execute the executable code on the electronic device responsive to determining that the lab certificate is valid and authenticating the code authentication certificate.

2. The electronic device of claim 1, wherein for a second operational condition of the plurality of operational conditions, the processor is configured to:

retrieve the code authentication certificate associated with the executable code;

authenticate the code authentication certificate by determining that a device identifier in the code authentication certificate matches the unique device identifier and that the code authentication certificate is signed with the private developer key and that the signature is valid, and

execute the executable code on the electronic device responsive to authenticating the code authentication certificate.

3. The electronic device of claim 1, wherein for a third operational condition of the plurality of operational conditions, the processor is configured to:

retrieve the code authentication certificate associated with the executable code;

authenticate that the code authentication certificate is signed with a private release key and that the signature is valid;

execute the executable code on the electronic device responsive to authenticating the code authentication certificate.

4. The electronic device of claim 1, wherein the processor is configured to authenticate the code authentication certificate by further determining that the public developer key is rooted by a trust anchor of the electronic device.

5. The electronic device of claim 1, wherein the lab certificate is valid when the processor authenticates the lab certificate using a public key rooted by a trust anchor of the electronic device to verify a digital signature of the lab certificate, and verifies that a device identifier in the lab certificate matches the unique device identifier.

6. The electronic device of claim 1, wherein the processor is configured to at least one of:

install the lab certificate on the electronic device independent of other software operations on the electronic device; and

remove the lab certificate from the electronic device independent of other software operations on the electronic device.

7. The electronic device of claim 1, wherein the lab certificate is at least one of a development certificate and a debugging certificate used to enable at least one of a development activity and a debugging activity executed on the electronic device, wherein the at least one development certificate and debugging certificate includes a device identifier.

8. The electronic device of claim 1, wherein the lab certificate comprises an expiration value and wherein determining that the valid lab certificate is present comprises determining based on the expiration value of the lab certificate that the lab certificate has not expired.

9. The electronic device of claim 8, wherein the expiration value is one of a time stamp and a first counter value and wherein determining that the lab certificate has not expired comprises one of:

determining, by the processor, a time value and comparing the time stamp to the time value; and

determining, by the processor, a second counter value and comparing the first counter value to the second counter value.

10. The electronic device of claim 1, wherein the processor is configured to execute the instructions associated with the plurality of signing states from a secure memory area.

11. The electronic device of claim 1, wherein the processor is configured to execute the lab certificate authentication and store authentication results for subsequent lab certificate verification.

12. A method for an electronic device to execute code, the method comprising:

maintaining, by the electronic device, a unique device identifier;

retrieving, by the electronic device, a code authentication certificate associated with an executable code to be executed on the electronic device;

determining, by the electronic device, whether a lab certificate is present in the electronic device;

in response to determining that a lab certificate is present, executing, by the electronic device, the executable code on the electronic device responsive to determining that the lab certificate is valid and that the code authentication certificate is signed with a private developer key and that the signature is valid.

13. The method of claim 12, wherein the method further comprises:

executing the executable code on the electronic device responsive to authenticating the code authentication certificate and determining that a device identifier in the code authentication certificate matches the unique device identifier.

14. The method of claim 12, wherein determining that the lab certificate is valid further comprises:

using a public lab certificate key associated with the lab certificate to verify a signature of the lab certificate, and verifying that a device identifier in the lab certificate matches the unique device identifier.

15. The method of claim 12, wherein authenticating the lab certificate further comprises using a public lab certificate key associated with the lab certificate to verify a signature of the lab certificate, and verifying that a device identifier in the lab certificate matches the unique device identifier.

16. The method of claim 12, further comprising at least one of:

installing the lab certificate on the electronic device independent of other software operations on the electronic device; and

removing the lab certificate from the electronic device independent of other software operations on the electronic device.

17. The method of claim 12, further comprising using the lab certificate as at least one of a development certificate and a debugging certificate to enable at least one of a development activity and a debugging activity executed on the electronic device, wherein the at least one development certificate and debugging certificate includes a device identifier.

18. The method of claim 12, wherein authenticating the lab certificate comprises determining based on an expiration value of the lab certificate that the lab certificate has not expired.

19. The method of claim 18, wherein the expiration value is one of a time stamp and a first counter value and wherein determining that the lab certificate has not expired comprises one of:

determining, by the processor, a time value and comparing the time stamp to the time value; and

determining, by the processor, a second counter value and comparing the first counter value to the second counter value.

20. A method for an electronic device to execute code, the method comprising:

maintaining, by the electronic device, a unique device identifier;

identifying, by the electronic device, a key that can be utilized to verify a code authentication certificate associated with the code;

determining, by the electronic device, that the code authentication certificate is valid by verifying a signature of the code authentication certificate using the key;

determining whether the key is a public release key or a public developer key rooted by a trust anchor of the electronic device;

in response to determining that the key is a release key and to determining that the code authentication certificate is valid, executing, by the electronic device, the code;

in response to determining that the key is a public developer key, determining whether a valid lab certificate is present on the electronic device;

in response to determining that the key is a public developer key, determining that the code authentication certificate is valid and that a valid lab certificate is present on the electronic device, executing, by the electronic device, the code.

21. The method of claim 20, further comprising:

in response to determining that the key is a public developer key and that a valid lab certificate is not present on the electronic device, determining whether the code authentication certificate comprises a device identifier and whether the device identifier matches the unique device identifier; and

in response to determining that the key is a public developer key, determining that the code authentication certificate is valid, that the code authentication certificate comprises a device identifier, and that the device identifier matches the unique device identifier, executing, by the electronic device, the code.

22. The method of claim 20, wherein determining that the lab certificate is valid further comprises using a public lab certificate key associated with the lab certificate to verify a signature of the lab certificate, and verifying that a device identifier in the lab certificate matches the unique device identifier.