Abstract: The invention relates to methods of interleaving payload data and integrity control data in an external memory interfaced with a microcontroller to improve data integrity check, enhance data confidentiality and save internal memory. Data words and are received for storing in the external memory. Each data word is used to generate a respective integrity word, while an associated logic address is translated to two physical addresses in the external memory, one for the data word and the other for the integrity word. The two physical addresses for the data and integrity words are interleaved in the external memory, and sometimes, in a periodic scheme. In particular, each data word may be associated to an integrity sub-word included in an integrity word having the same length with that of a data word. The external memory may have dedicated regions for the data words and the integrity words, respectively.