A control device is connected to at least one encryption/decryption device
via at least one communication device. The control device is connected to
a round key generator via at least one further communication device. The
control device has at least one external key input, the at least one
encryption/decryption device has at least one external data input and at
least one external data output, and the at least one
encryption/decryption device and the round key generator are decoupled
from one another.