A plurality of functional blocks can preferably also be arranged in one level, wherein the respective same number of authentication processes is required for the functional blocks in one level. Access to all the functional blocks of the level can, however, not be automatically granted on an authentication for one functional block. Instead, a complete repeat authentication can be required for every functional block of the level.

The hierarchy of the levels disposed above one another can be purely virtual or can be provided by a corresponding consecutive connection of hardware of the embedded device. The advantage additionally results due to the division of the functionality of the embedded device into a plurality of functional blocks that only parts of the functionality of the embedded device are released on a successful attack.

If a user is authenticated for a level, he can access the functions of functional blocks, i.e. he can utilize their functionality and can, for example, change the embedded device, read out parameters or control connected further devices.

Advantageous embodiments of the invention can be seen from the description, from the dependent claims and from the drawings.