Arrangement and method of execution of code

• US 20040243810A1
• Filed: 03/19/2004
• Published: 12/02/2004
• Est. Priority Date: 09/21/2001
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Halen, Joachim, Rindborg, Tom
• Granted Patent: US 7,370,211 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: G06F 21/123 by using dedicated hardware, e.g. dongles, smart cards, cryptographic processors, global positioning systems [GPS] devices
• CPC Class Codes: G06F 21/52 during program execution, e.g. stack integrity ; Preventing unwanted data erasure; Buffer overflow
• CPC Class Codes: G06F 21/567 using dedicated hardware

Abstract

The present invention relates to systems (1) and a method for executing code. According to the method a non-critical code portion is executed on a computer (3). When an application (5) on the computer detects a critical code portion to be executed, the application sends a request to a secure execution unit (4) connected to the computer to execute the critical code portion. The secure execution unit (4) executes the critical code portion in response to the request. Thereafter the secure execution unit authenticates the result of the execution of the critical code portion using a secret key (7). The authentication allows for another party (2) to verify that the execution was carried out in a trusted way. An advantage of the present invention is that it provides a reliable execution environment that can be trusted to execute critical code.

Claims

1. A system for executing code, comprising critical code portions and non-critical code portions, wherein the system comprises:

a computer having at least one application,

a secure execution unit connected to the computer, wherein the secure execution unit includes;

means for executing the critical code portions,

means for storing a secret key, and

means for authenticating a result of an executed critical code portion using the secret key;

wherein the at least one application is arranged to send a request to the secure execution unit to execute a first critical code portion.

2. The system according to claim 1, wherein the secure execution unit includes means for checking a digital signature of the first critical code portion.

3. The system according to claim 2, that wherein the secure execution further has communications means for forwarding the authenticated result to a server.

4. The system according to claim 3, wherein the secure execution unit has communications means for forwarding the authenticated result to the application on the computer.

5. The system according to claim 4, wherein the secure execution unit includes a clock unit and means for time stamping the result.

6. The system according to claim 5, wherein the means for authenticating the result includes digital signing means.

7. The system according to claim 6, wherein the means for authenticating the result includes encryption means.

8. The system according to claim 7, wherein the application is arranged to include at least one parameter to the first critical code portion in the request to the secure execution unit.

9. The system according to claim 8, wherein the secure execution unit includes a memory for storing at least one predetermined constraint of the at least one parameter and means for comparing the parameter with the at least one predetermined constraint.

10. The system according to claim 8, wherein the secure execution unit has a display and an input device and the secure execution unit is arranged to display the at least one parameter on the display.

11. The system according to claim 10, wherein the secure execution unit is a hardware unit that is separate from the hardware of the computer and in that the secure execution unit and the computer have communications interfaces for communicating with each other.

12. The system according to claim 10, wherein the secure execution unit is incorporated in the same chassis as the computer.

13. A processing system including a first subsystem and a second subsystem, wherein at least the first system comprises:

a computer having at least one application,

a secure execution unit connected to the computer, wherein the secure execution unit includes;

means for executing the critical code portions,

means for storing a secret key, and

means for authenticating a result of an executed critical code portion using the secret key;

wherein the at least one application is arranged to send a request to the secure execution unit to execute a first critical code portion.

14. The processing system according to claim 13, wherein at least the second system has means for checking an authenticated result of an execution of a critical code portion in the secure execution unit and verifying that the execution was carried out in a trusted way.

25. The processing system according to claim 13, wherein the secure execution unit includes means for checking a digital signature of the first critical code portion.

26. The system according to claim 25, wherein the secure execution further has communications means for forwarding the authenticated result to a server.

27. The system according to claim 26, wherein the secure execution unit has communications means for forwarding the authenticated result to the application on the computer.

28. The system according to claim 27, wherein the secure execution unit includes a clock unit and means for time stamping the result.

29. The system according to claim 28, wherein the means for authenticating the result includes digital signing means.

30. The system according to claim 29, wherein the means for authenticating the result includes encryption means.

31. The system according to claim 30, wherein the application is arranged to include at least one parameter to the first critical code portion in the request to the secure execution unit.

32. The system according to claim 31, wherein the secure execution unit includes a memory for storing at least one predetermined constraint of the at least one parameter and means for comparing the parameter with the at least one predetermined constraint.

33. The system according to claim 31 wherein the secure execution unit has a display and an input device and the secure execution unit is arranged to display the at least one parameter on the display.

34. The system according to claim 33, wherein the secure execution unit is a hardware unit that is separate from the hardware of the computer and in that the secure execution unit and the computer have communications interfaces for communicating with each other.

35. The system according to claim 33, wherein the secure execution unit is incorporated in the same chassis as the computer.

15. A method for executing code, comprising critical code portions and non-critical code portions, which method includes the step of executing at least a first non-critical code portion on a computer, further comprising the steps of:

an application on the computer detecting a first critical code portion to be executed;

the application sending a request to a secure execution unit to execute the first critical code portion;

the secure execution unit executing the first critical code portion in response to the request; and

the secure execution unit authenticating the result of the execution of the first critical code portion using a secret key.

16. The method according to claim 15, further comprising the step of the secure execution unit verifying the authenticity of the first critical code portion before executing it by means of checking a digital signature of the first critical code portion.

17. The method according to claim 15, further comprising the step of the secure execution unit authenticating the result by means of signing it digitally using the secret key.

18. The method according to claim 15, further comprising the step of the secure execution unit authenticating the result by means of encrypting it using the secret key.

19. The method according to claim 15, further comprising the step of the application including at least one parameter to the first critical code portion in the request to the secure execution unit.

20. The method according to claim 19, further comprising the step of the secure execution unit checking the validity of the at least one parameter by means of comparing the parameter with at least one predetermined constraint.

21. The method according to claim 19, further comprising the step of the secure execution unit displaying the at least one parameter on a display in order for a user to visually inspect the validity of the parameter.

22. The method according to claim 15, the further comprising the steps of:

the secure execution unit forwarding the authenticated result to a foreign system,

the foreign system checking the result and

verifying that the execution was carried out in a trusted way.

23. The method according to claim 22, comprising the step of the secure execution unit forwarding the authenticated result to the foreign system via the application on the computer.

24. The method according to claim 22, further comprising the steps step of:

the secure execution unit time stamping the result and

the foreign system also checking the time stamp of the result when the execution is verified to have been carried out in a trusted way.