ESP8266 Community Forum

QuickFix wrote:You *might* be able to come up with some scheme that reads the unique serial of the ESP and check that upon boot

According to this ESP.getChipId() does not return a unique chip number.
They suggest the MAC address but how do I get it? Is there something like 'ESP.getMAC()'?
Or maybe it's the WiFi.macAddress()?

ESP.getChipId() is based on last 3 octets of the mac address so although not unique is unlikely to be repeated in a reasonable population.

WiFi.macAddress() is the arduino call to get the full mac address (6 octets with separating ':') It is expected to be unique. If someone guessed that you were checking this then they could replicate the mac address but it might make deployment trickier for them as all the copies based on one original would have the same mac address.

Ok guys, thank you!

Restricting access to the code is inherently impossible on the esp8266 because the flash can always be read (either using the boot loader or by desoldering the flash chip. It cannot do on-the-fly decryption like the esp32 can.

So what you're trying to do is impossible (even though some schemes SEEM plausible).

I think it's pretty lame to try to "protect" software. Better share it indeed, so you can also profit from other's contributions.