Changes

The SAM4L has a hardware AES module, with optional countermeasures that can be enabled. These countermeasures are described in the SAM4L datasheet as the following options:  * Type 1: Randomly add one cycle to data processing * Type 2: Randomly add one cycle to data processing (other version) * Type 3: Add a random number of clock cycles to data processing, subject to a maximum of 11 clock cycles for key size of 128 bits * Type 4: Add random spurious power consumption during data processing Interestingly they can be individually enabled/disabled. This makes the SAM4L a useful training target for power analysis attacks against various hardware countermeasures.