Abstract: Process for protecting components of smart cards from fraudulent use, wherein the component is locked as long as an unlock order formed by a secret key has not been applied thereto, characterized in that it consists in writing in the component, at the time of its manufacture, a value and a result, the result being associated with the said value by a given algorithm and the secret key.

Abstract: Process and memory card (1) for making secure the writing of sensitive data into the EEPROM data storage memory (2) of the card, consisting, during each write, in performing the following operations in succession:a) registering the start address of the data area (Ze) of the card to which a write is to be performed, into an address field (Za) of the memory);b) reading the data present in this data area (Ze) of the memory;c) storing the read data in a save area (Zs) of the memory;d) writing the "WRITE IN PROGRESS" datum into a flag area (Zd) of the memory;e) performing the write to the data area (Ze) of the memory; andf) writing the "NO WRITE IN PROGRESS" datum into the flag area (Zd) of the memory.