Process for securing and for checking the integrity of the secured programs
First Claim
1. In a data processing system having a memory and at least one executable program, a method of protecting against the execution of programs altered without authorization, the method comprising the steps of:
- storing in said computer system a reference checksum generated on the basis of an authorized version of the at least one program by execution of a predetermined cryptographic algorithm;
generating a program checksum on the basis of a version of the at least one program presented for execution in the computer system, by execution of the predetermined cryptographic algorithm;
comparing the generated program checksum with the stored reference checksum; and
blocking execution of the at least one program when the generated checksum differs from the reference checksum.
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Accused Products
Abstract
For securing programs contained in a system storage and for checking their integrity, the programs are in each case coded by a symmetric cryptographic algorithm with the application of a readback secured, secret key, and a check number for each program is simultaneously formed and stored in the storage of the system. For checking the integrity, the programs are then coded again in the same manner and the check number thus obtained in each case is compared with the check number stored at the first coding. It is possible to derive from the result of comparison a criteria for activation or locking the following programs.
161 Citations
13 Claims
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1. In a data processing system having a memory and at least one executable program, a method of protecting against the execution of programs altered without authorization, the method comprising the steps of:
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storing in said computer system a reference checksum generated on the basis of an authorized version of the at least one program by execution of a predetermined cryptographic algorithm; generating a program checksum on the basis of a version of the at least one program presented for execution in the computer system, by execution of the predetermined cryptographic algorithm; comparing the generated program checksum with the stored reference checksum; and blocking execution of the at least one program when the generated checksum differs from the reference checksum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. In a data processing system comprising an administrative computer and at least one target computer and at least one target computer program to be executed on the target computer, a method of protecting against the execution of programs altered without authorization, the method comprising the steps of:
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generating a reference checksum on the basis of an authorized version of the at least one target computer program by execution of a predetermined cryptographic algorithm in the administrative computer; storing the reference checksum in a portable memory carrier; transferring the carrier to the target computer; generating a program checksum on the basis of a version of the at least one program presented for execution in the target computer, by execution of the predetermined cryptographic algorithm; comparing the generated program checksum with the reference checksum; and executing the at least one program in the target computer only when the comparison indicates that the generated checksum is equal to the corresponding reference checksum. - View Dependent Claims (13)
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Specification