Cryptographic processor, method for implementing a cryptographic processor and key generation circuit

A method for implementing a cryptographic processor comprising:

• forming a processing circuit configured to perform a round function of an iterated cryptographic algorithm;
• forming a controller configured to control the processing circuit to apply a plurality of iterations of the round function on a message to process the message in accordance with the iterated cryptographic algorithm;
• forming a transformation circuit configured to transform the input of a second iteration of the round function following a first iteration of the round function of the plurality of iterations and to supply the transformed input as input to the second iteration;
• wherein the transformation circuit comprises one or more cells having an internal feedback loop configured to have a fixed output and a dynamic output.