Patent ID: 8781114

Claim:
An apparatus for recognizing a failure in a cryptographic unit, with the cryptographic unit being formed to determine output signals from input signals, and with the apparatus for recognizing comprising: a determinator configured to determine at least one input control signal and at least one output control signal, with the determinator being formed to determine the input control signal on the basis of an encryption of an input signal control parity of a group of the input signals or an input signal of the group of input signals with an encryption number and to determine the output control signal on the basis of an encryption of an output signal control parity of a group of the output signals or an output signal of the group of output signals with the encryption number; and an evaluator configured to evaluate the input control signal and the output control signal to recognize a failure of the cryptographic unit on the basis of a comparison between the input control signal and the output control signal; wherein the cryptographic unit is formed to use a cryptographic key configured to determine the output signals from the input signals, and wherein the determinator is formed to encrypt the cryptographic key with the encryption number.