Prevent Modification of NVS Data

[GerryTitan]

Hello,

Is there a way to prevent unauthorized modification of data in the NVS partition (for example, via esptool write_flash)?

Thanks.

[jcsbanks]

You could encrypt it.

[GerryTitan]

You could encrypt it.

That's true, but there is still the possibility that an attacker can modify/corrupt the data, right?

[WiFive]

If NVS encryption is not used, it is possible for anyone with physical access to the flash chip to alter, erase, or add key-value pairs. With NVS encryption enabled, it is not possible to alter or add a key-value pair and get recognized as a valid pair without knowing corresponding NVS encryption keys. However, there is no tamper-resistance against the erase operation.

[GerryTitan]

Is it possible to just disable the UART interface to the chip so that physical tampering is impossible?

[WiFive]

No, and even if you did it would be possible to connect directly to the flash chip. For some physical protection you'd have to encapsulate.

[GerryTitan]

Okay, thank you for the explanation. I guess apps should just be robust enough to anticipate tampering/erasing of NVS data. I will consider this for the future.