A cryptographic method includes providing memory locations for storing encrypted data. The memory locations have respective addresses and are accessible via a communication bus. The method includes receiving over the communication bus access requests to the memory locations, wherein the access requests include burst requests for access to respective sets of the memory locations starting from respective start addresses, and calculating as a function of the start addresses encryption/decryption cryptographic masks based on cryptographic keys. Plain text data is received for encryption and the method includes applying the cryptographic masks to the plain text data to obtain therefrom encrypted data, and including the encrypted data into output data for transmission over the communication bus.