摘要 |
The invention concerns an electronic data processing circuit having an operating module (1, 101), such as for example a microprocessor, with at least one data memory (2, 3, 4, 5, 102, 103, 104, 105) and with a data bus (106) extending between a data memory (2, 3, 4, 5, 102, 103, 104, 105) and the operating module (1, 101). With electronic data processing circuits of the type in question the memory frequently contains information to which access should be limited as far as possible. Therefore it is necessary to take security measures to guard against manipulation of the electronic data processing circuit. Consequently the object of the invention is to produce an electronic data processing circuit of the type in question which affords better protection against undesired alterations. According to the invention, this object is achieved by an electronic data processing circuit of the type in question in which at least one coding module (20, 21, 22, 35, 107) is provided in the region between the data memory (2, 3, 4, 5, 102, 103, 104, 105) and the data bus and/or in the region between the operating module (1, 101) and the data bus. The coding module (20, 21, 22, 35, 107) is designed such that data traffic between the operating module (1, 101) and the data bus or between the data memory (2, 3, 4, 5, 102, 103, 104, 105) and the data bus (106) can be coded and/or decoded.
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