Non-volatile memory devices are becoming more and more widespread as the request for data storage continues to increase with present electronic applications. Flash EEPROMs memories, either with NAND or with NOR architecture, are the most popular type of non-volatile memory because of a number of advantages, among which are high integration density, fast write/erase speed, and compatibility with conventional CMOS processes.
One important feature of non-volatile memories is their security, especially to avoid undesired, accidental modification of existing data in the memory.
Modern applications need to access to the memory with a fine and varied granularity, and often the information stored has different requirements in terms of protection from accidental modification. In some cases the data or programs require a limited memory space. Moreover, the memory content changes several times during its life in the field.
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