I use them in an esp32 to write a random password to each of my products, so when I sell them they can each have their own secure default wifi password while all using the same firmware.

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josephcsible 5 hours ago | parent [-]

What advantage do you see from using eFuses and not some other way to store the password?

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thesh4d0w 5 hours ago | parent [-]

This is the only way I could come up with that would allow an end user to do a full factory reset, and end up back in a known good secure state afterwards.

Storing it in the firmware would mean every user has the same key. Storing it in eeprom means a factory reset will clear it. This allows me to ship hardware with the default key on a sticker on the side, and let's a non technical user reset it back to that if they need to.

It gives you a 256bit block to work with - https://docs.espressif.com/projects/esp-idf/en/stable/esp32/...

	▲	josephcsible 4 hours ago \| parent [-]
		But couldn't you also just set aside a bit of the EEPROM your factory reset skips, and accomplish the same thing?