52.5.2.1 Description

To enter Automatic Bridge mode, TZAESB_MR.OPMOD must be configured to 0x4.

When the TZAESB is connected to the system bus with both Client and Host ports, the Automatic Bridge mode provides automatic encryption/decryption without any action by the user. If TZAESB_MR.OPMOD = 0x4, there is no compliance with the standard CTR mode of operation but the mode of operation is derived from CTR mode.

In case of a write transfer, this mode automatically encrypts the data before writing it to the final client destination. In case of a read transfer, this mode automatically decrypts the data read from the target client before putting it on the system bus.

Therefore, this mode does not work if the automatically encrypted data is moved to another address outside of the TZAESB. Thus for a given data, the encrypted value is not the same if written at different addresses.