System and Method for Providing a Secure Application Fragmentation Environment

• US 20090300366A1
• Filed: 05/30/2008
• Published: 12/03/2009
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Gueller, Markus, Hewel, Harald
• Granted Patent: US 8,478,973 B2
• Time in Patent Office: Days
• US Class Current: 713/189
• 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: G06F 9/445 Program loading or initiating bootstrapping G06F9/4401; security arrangements for program loading or initiating G06F21/57

Abstract

System and method for providing and using expanded memory resources secure application environment is disclosed. An embodiment comprises a system and method for providing secure application functionality comprising receiving a request for a secure operation; determining if required application code for the secure operation is present in an application fragment store; sequentially loading a plurality of fragments of the required application code from an external memory, if the required application code is not present in the application fragment store; sequentially executing the plurality of fragments of the required application code; and sending a reply to the request for the secure operation. The system and method may further comprise decrypting each of the plurality of fragments of the required application code using a secure key prior to execution of the fragment and verifying the integrity of the code fragment.

Claims

1. A system comprising:

a secure fragmentation manager coupled to an application fragments store;

an external memory interface coupled to the secure fragmentation manager, the secure fragmentation manager obtaining a required code fragment from an external memory via the external memory interface, if the required code fragment is not present in the application fragments store;

a cryptographic engine coupled to the application fragments store and a secure key store, the cryptographic engine decrypting the required code fragment, if necessary, using a secure key and verifying the integrity of a code fragment; and

an execution engine coupled to the cryptographic engine and application fragments store, the execution engine executing a decrypted code fragment.

2. The system of claim 1, wherein the size of the application store is selected based upon a minimum useable code fragment size.

3. The system of claim 1, further comprising:

a system interface coupling a system application command to the secure fragmentation manager.

4. The system of claim 3, wherein the system application command is an authentication operation request, key management command, secure storage command, secure platform reporting command or secure boot operation.

5. The system of claim 1, wherein the secure fragmentation manager, application fragments store, cryptographic engine and execution engine are part of secure application fragmentation environment (SAFE), the system further comprising:

a system interface coupling the SAFE to a central processing unit on a Printed Circuit Board (PCB).

6. The system of claim 1, wherein the secure fragmentation manager, application fragments store, cryptographic engine and execution engine are part of secure application fragmentation environment (SAFE), the SAFE residing in a system on a chip (SoC);

the system further comprising;

a system interface coupling the SAFE to a microcontroller on the SoC.

7. The system of claim 1, wherein the secure fragmentation manager determines if the required code fragment is present in the application store.

8. The system of claim 1, further comprising:

a memory management unit coupled to the execution engine and to the secure fragmentation manager.

9. The system of claim 1, further comprising:

a hash engine providing the integrity verification for code fragments.

10. The system of claim 1, wherein the external memory is non-volatile memory (NVM).

11. The system of claim 10, wherein the NVM comprises flash memory;

Electrically Erasable Programmable Read-Only Memory (EEPROM);

Erasable Programmable Read-Only Memory (EPROM);

Magnetic RAM (MRAM);

Ferroelectric RAM (FeRAM);

Programmable Metallization Cell (PMC);

or Phase-change Memory (PCM).

12. The system of claim 11, wherein the external memory interface is a disk drive interface.

13. The system of claim 12, further comprising:

an external magnetic memory or optical storage device.

14. The system of claim 1, wherein the secure fragmentation manager comprises logic implemented in non-volatile memory.

15. The system of claim 1, wherein the application fragments store comprises volatile memory.

16. The system of claim 15, wherein the volatile memory comprises SRAM or DRAM.

17. The system of claim 1, wherein the secure key store comprises a non-volatile memory (NVM).

18. The system of claim 17, wherein the NVM comprises one-time programmable (OTP) memory, battery buffered RAM, or flash memory.

19. A method for providing secure application functionality, comprising:

receiving a request for a secure operation;

determining if a required application code fragment for the secure operation is present in an application fragment store;

loading the required application code fragment from an external memory, if the required application code fragment is not present in the application fragment store;

decrypting the required application code fragment using a secure key;

verifying the integrity of a required application code fragment;

executing the decrypted required application code fragment; and

sending a reply to the request for the secure operation.

20. The method of claim 19, wherein the request for a secure operation originates from a central processing unit on a Printed Circuit Board or a microcontroller on a system on a chip (SoC).

21. The method of claim 19, wherein the external memory is a non-volatile memory (NVM) device.

22. The method of claim 19, wherein the external memory is a magnetic memory device or optical storage device.

23. The method of claim 19, further comprising:

loading a second required application code fragment from the external memory, if the second required application code fragment is not present in the application fragment store;

decrypting the second required application code fragment using the secure key;

verifying the integrity of a second required application code fragment; and

executing the second decrypted required application code fragment.

24. The method of claim 19, wherein the secure operation is an authentication operation request, key management command, secure storage command, secure platform reporting command or secure boot operation.

25. The method of claim 19, wherein the request for the secure operation originates during a boot function.

26. A method for providing secure application functionality, comprising:

receiving a request for a secure operation;

determining if required application code for the secure operation is present in an application fragment store;

sequentially loading a plurality of fragments of the required application code from an external memory, if the required application code is not present in the application fragment store;

sequentially executing the plurality of fragments of the required application code; and

sending a reply to the request for the secure operation.

27. The method of claim 26, further comprising:

decrypting each of the plurality of fragments of the required application code using a secure key prior to execution of the fragment; and

verifying the integrity of each of the plurality of required application code fragments.