Integrated circuit having an active shield

1. An integrated circuit comprising:

security-critical circuit components arranged in a lower plane;

data lines arranged in an upper plane, situated at least in part above the security-critical circuit components arranged in the lower plane, and connected to the security-critical circuit components; and

a detector circuit that identifies an attack on the integrated circuit, comprising:

a transmitting device that transmits predetermined test data into the security-critical circuit components arranged in the lower plane;

a receiving device that receives the data processed by the security-critical circuit components arranged in the lower plane; and

an evaluation device that compares the received data with expected data and that ascertains any non-correspondence,

wherein the integrated circuit is operable in a normal mode and a test mode,

the data lines carry the predetermined test data that is transmitted by the transmitting device and is processed by the security-critical circuit components in the test mode, and

the data lines carry data that is processed by the security critical circuit components in the normal mode.

2. The integrated circuit according to claim 1 , wherein the security-critical circuit components are parts of an encryption device.

3. The integrated circuit according to claim 2 , wherein the encryption device is a DES encryption device.

4. The integrated circuit according to claim 1 , wherein the transmitter transmits the predetermined test data in cyclic intervals.

5. The integrated circuit according to claim 1 , wherein the transmitter transmits the predetermined test data at irregular time intervals.

6. An integrated circuit comprising:

security-critical circuit components arranged in a lower plane, and which are parts of an encryption device;

data lines arranged in an upper plane, situated at least in part above the security-critical circuit components arranged in the lower plane, and connected to the security-critical circuit components;

a memory, in which second data that is necessary to encrypt first data is stored, connected by the data lines to processing units, which combine the first data with the second data and a key; and

a detector circuit that identifies an attack on the integrated circuit, comprising:

a transmitting device that transmits predetermined test data into the security-critical circuit components arranged in the lower plane;

a receiving device that receives the data processed by the security-critical circuit components arranged in the lower plane; and

an evaluation device that compares the received data with expected data and ascertains any non-correspondence,

wherein the data lines carry data that is necessary during the processing of transmitted data.

7. The integrated circuit according to claim 6 , further comprising a test key, which is stored in a key register and encrypts the test data.

8. The integrated circuit according to claim 6 , wherein the transmitter transmits the predetermined test data in cyclic intervals.

9. The integrated circuit according to claim 6 , wherein the transmitter transmits the predetermined test data at irregular time intervals.

10. The integrated circuit according to claim 6 , wherein the encryption device is a DES encryption device.

11. An integrated circuit comprising:

security-critical circuit components arranged in a lower plane;

data lines arranged in an upper plane, situated at least in part above the security-critical circuit components arranged in the lower plane, and connected to the security-critical circuit components; and

a detector means for identifying an attack on the integrated circuit, comprising:

a transmitting means for transmitting predetermined test data into the security-critical circuit components arranged in the lower plane;

a receiving means for receiving the data processed by the security-critical circuit components arranged in the lower plane; and

an evaluation means for comparing the received data with expected data and that ascertains any non-correspondence,

wherein the integrated circuit is operable in a normal mode and a test mode,

the data lines carry the predetermined test data that is transmitted by the transmitting means and is processed by the security-critical circuit components in the test mode, and

the data lines carry data that is processed by the security critical circuit components in the normal mode.

12. An integrated circuit comprising:

security-critical circuit components arranged in a lower plane, which are parts of an encryption device;

data lines arranged in an upper plane, situated at least in part above the security-critical circuit components arranged in the lower plane, and connected to the security-critical circuit components;

a memory, in which second data that is necessary to encrypt first data is stored, connected by the data lines to processing units, which combine the first data with the second data and a key; and

a detector means for identifying an attack on the integrated circuit, comprising:

a transmitting means for transmitting predetermined test data into the security-critical circuit components arranged in the lower plane;

a receiving means for receiving the data processed by the security-critical circuit components arranged in the lower plane; and

an evaluation means for comparing the received data with expected data and that ascertains any non-correspondence,

wherein the data lines carry the first data that is necessary during the processing of transmitted data.