Method for protecting a microcomputer system against manipulation of data stored in a storage assembly

• US 7,313,703 B2
• Filed: 07/01/2002
• Issued: 12/25/2007
• Est. Priority Date: 07/02/2001
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Beuten, Michael, Schneider, Klaus, Illg, Bernd
• Primary Examiner(s): Moazzami, Nasser
• Assistant Examiner(s): Baum, Ronald
• Application Number:
  US10/187,815
• Publication Number:
  US 20030018902A1
• Time in Patent Office: 2,003 Days
• Field of Search: 713187-194
• US Class Current: 713/187
• CPC Class Codes: G11C 16/22 Safety or protection circuits preventing unauthorised or accidental access to memory cells

Abstract

A method of protecting a microcomputer system against manipulation of data stored in a storage assembly of the microcomputer system, in particular a control program stored there. Checking mechanisms are executed at preselectable points in times to check for manipulation of the data. To achieve the most complete test coverage within an acceptable period of time in checking data stored in a storage assembly of a microcomputer system, the storage assembly is subdivided into multiple logic blocks, at least one of the blocks is selected and the checking mechanisms are executed only for the or each selected block of the storage assembly.

Claims

1. A computer readable medium having a program executable by a processor, comprising:

a program code for performing a method of protecting a microcomputer system against manipulation of data stored in a storage assembly of the microcomputer system, the method including;

subdividing the storage assembly into a plurality of logic blocks; and

at each of a plurality of preselectable points in time;

selecting only a corresponding subset of the plurality of logic blocks that includes less than all of the data; and

executing at least one check operation to check for manipulation of only the data of the corresponding subset.

2. The computer readable medium of claim 1, wherein the data stored in the storage assembly includes a control program.

3. The computer readable medium of claim 1, wherein the at least one check operation is executed in powering up the microcomputer system.

4. The computer readable medium of claim 1, wherein the corresponding subset is selected randomly.

5. The computer readable medium of claim 4, further comprising:

reading a noise signal at an analog/digital input of the microcomputer system;

generating a random number as a function of the noise signal;

forming a sum of contents in the storage assembly, the contents being disordered before the microsystem is powered up;

generating a random number as a function of the sum;

reading out a status of a timer inside the microcomputer system that is not reset when the microsystem is powered up;

generating a random number as a function of the status of the timer;

reading out a variable influenceable by a driver of a vehicle into which the microcomputer system is integrated; and

generating a random number as a function of the variable.

6. The computer readable medium of claim 1, further comprising:

storing, after executing the at least one check operation, an entry into a storage area of the storage assembly in a write-protected form and one that may not be read out;

erasing the storage area when one of reprogramming and newly programming the storage assembly; and

checking the entry when the microcomputer system is powered up.

7. The method of claim 1, wherein a number and a size of the plurality of logic blocks is selected as a function of at least one of a computing power of a microprocessor of the microcomputer and a size of a storage assembly of the microcomputer.

8. The method of claim 1, wherein at least one of the following is satisfied:

(1) the selecting of the corresponding subset is limited to those of the logic blocks in which new data has been stored; and

(2) the selecting of the corresponding subset is random.

9. The method of claim 1, wherein different ones of the plurality of logic blocks are checked in successive power-ups of the microcomputer, so that stochastically over time substantially complete test coverage is obtained.

10. The method of claim 1, wherein:

a number and a size of the plurality of logic blocks is selected as a function of at least one of a computing power of a microprocessor of the microcomputer and a size of a storage assembly of the microcomputer;

the selecting of the corresponding subset is limited to those logic blocks in which new data has been stored;

the selecting of the corresponding subset is random; and

different ones of the plurality of logic blocks are checked in successive power-ups of the microcomputer, so that stochastically over time substantially complete test coverage is obtained.

11. A microcomputer system comprising:

a computer;

a storage assembly to store data;

a subdividing arrangement to subdivide the storage assembly into a plurality of logic blocks; and

for protection against manipulation of the data;

a selecting arrangement to select, at each of a plurality of preselectable points in time, only a corresponding subset of the plurality of logic blocks that includes less than all of the data; and

an executing arrangement to execute at least one check operation at each of the preselectable points in time to check for manipulation of only the data of the corresponding subset.

12. The microcomputer system of claim 11, wherein the computer includes a microprocessor.

13. The microcomputer system of claim 11, wherein the data stored in the storage assembly includes a control program.

14. The microcomputer system of claim 11, wherein the microcomputer system is configured as a control device for a motor vehicle for one of controlling and regulating an automotive function.

15. The microcomputer system of claim 11, wherein the storage assembly is arranged on a same semiconductor component as the computer.

16. The microcomputer of claim 11, wherein at least two of the following are satisfied:

a number and a size of the plurality of logic blocks is selected as a function of at least one of a computing power of a microprocessor of the microcomputer and a size of a storage assembly of the microcomputer;

the selecting of the corresponding subset is limited to those logic blocks in which new data has been stored;

the selecting of the corresponding subset is random; and

different ones of the plurality of logic blocks are checked in successive power-ups of the microcomputer, so that stochastically over time substantially complete test coverage is obtained.

17. A microcomputer system comprising:

a computer;

a storage assembly to store data;

a computer readable medium having stored thereon a program executable by the computer, the computer program comprising program code for protecting the microcomputer system against manipulation of the data stored in the storage assembly of the microcomputer system by causing the computer to perform the steps of;

subdividing the storage assembly into a plurality of logic blocks; and

at each of a plurality of preselectable points in time;

selecting only a corresponding subset of the plurality of logic blocks that includes less than all of the data; and

executing at least one check operation to check for manipulation of only the data of the corresponding subset.

18. A memory having stored thereon a computer program executable by a computer, the computer program comprising program code, which when executed by the computer, cause the computer to perform a method for protecting a microcomputer system against manipulation of data stored in a storage assembly of the microcomputer system, the method comprising:

subdividing the storage assembly into a plurality of logic blocks; and

at each of a plurality of preselectable points in time;

selecting only a corresponding subset of the plurality of logic blocks that includes less than all of the data; and

executing at least one check operation to check for manipulation of only the corresponding subset.

19. The computer program of claim 18, wherein at least two of the following are satisfied:

a number and a size of the plurality of logic blocks is selected as a function of at least one of a computing power of a microprocessor of the microcomputer and a size of a storage assembly of the microcomputer;

the selecting of the corresponding subset is limited to those logic blocks in which new data has been stored;

the selecting of the corresponding subset is random; and

different ones of the plurality of logic blocks are checked in successive power-ups of the microcomputer, so that stochastically over time substantially complete test coverage is obtained.