Method for booting up software in the boot sector of a programmable read-only memory

• US 20070005948A1
• Filed: 12/23/2005
• Published: 01/04/2007
• Est. Priority Date: 06/24/2003
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Kuhls, Burkhard, Kalverkamp, Thomas
• Granted Patent: US 7,584,350 B2
• Time in Patent Office: Days
• US Class Current: 713/1
• CPC Class Codes: G06F 8/65 Updates security arrangements therefor G06F21/57

Abstract

A method of booting up update software in a writable memory area of a boot sector of a programmable control device of a vehicle is provided. The method Provides a boot-up software that can be booted up in a writable memory area of the programmable control device which is situated outside the boot sector. The boot-up software is capable of controlling, in the control device, the installation of the update software in the writable memory area of the boot sector, booting up the boot-up software and the update software in the writable memory area situated outside the boot sector, and executing the boot-up software in the control device in order to install the update software in the writable memory area of the boot sector.

Claims

1. Method of booting up an update software in a writable memory area of a boot sector of a programmable control device of a vehicle, comprising the steps of:

providing a boot-up software that can be booted up in a writable memory area located outside the boot sector of the programmable control device, wherein the boot-up software can install the update software in the writable memory area of the boot sector;

booting up the boot-up software and the update software in the writable memory area situated outside the boot sector; and

executing the boot-up software in the programmable control device in order to install the update software in the writable memory area of the boot sector.

2. Method according to claim 1, wherein the update software is contained in the boot-up software.

3. Method according claim 2, further comprising the step of:

applying a signature process to at least a portion of the boot-up software or to the update software, wherein the at least a portion of the boot-up software or update software is signed before its transmission into the control device by a first signature key and, after its transmission into the control unit, is checked with respect to its integrity by means of a second signature key filed in the control device.

4. Method according to claim 3, further comprising the step of exchanging a key filed in the boot sector of the control device for a new key.

5. Method according to claim 3, further comprising the step of:

restoring memory contents of the boot sector of the control device after an uncontrolled physical change or for the subsequent introduction, expansion or updating of software-based safety mechanisms.

6. Method according to claim 3, further comprising the step of:

filing the second signature key in the writable memory area of the boot sector.

7. Method according to claim 6, wherein the signature process is an asymmetrical signature process, the first signature key and the second signature key forming a complementary pair of keys.

8. Method according to claim 7, further comprising the steps of:

encrypting and decrypting, wherein at least a portion of the boot-up software or of the update software, before the transmission into the control device, is encrypted by means of an encryption key and, after the transmission into the control device, is decrypted by a decryption software by means of a decryption key filed in the control device.

9. Method according to claim 8, wherein the decryption key is filed in the writable memory area of the boot sector.

10. Method according to claim 9, wherein the decryption software is contained in the boot-up software.

11. Method according claim 10, wherein a symmetrical encryption method is used, and the encryption key and the decryption key are identical.

12. Method according claim 10, wherein an asymmetrical encryption method is used, and the encryption key and the decryption key form a complementary pair of keys.

13. Method according to claim 12, wherein the first signature key and the encryption key are identical, and the second signature key and the decryption key are identical.

14. Method according to claim 12, wherein the first signature key and the encryption key are different, and the second signature key and the decryption key are different.

15. Method according of claim 6, wherein the signature process is a symmetrical signature process, and the first and the second signature keys are identical.

16. Method according to claim 15, further comprising the steps of:

encrypting and decrypting, wherein at least a portion of the boot-up software or of the update software, before the transmission into the control device, is encrypted by means of an encryption key and, after the transmission into the control device, is decrypted by a decryption software by means of a decryption key filed in the control device.

17. Method according to claim 16, wherein the decryption key is filed in the writable memory area of the boot sector.

18. Method according to claim 17, wherein the decryption software is contained in the boot-up software.

19. Method according claim 18, wherein a symmetrical encryption method is used, and the encryption key and the decryption key are identical.

20. Method according claim 18, wherein an asymmetrical encryption method is used, and the encryption key and the decryption key form a complementary pair of keys.

21. Method according to claim 17, wherein the first signature key and the encryption key are identical, and the second signature key and the decryption key are identical.

22. Method according to claim 17, wherein the first signature key and the encryption key are different, and the second signature key and the decryption key are different.