Im pretty dumb founded when it comes to computer hardware and components this looks like some hotwired hacker thingy I don't even know what it would be used for. What do you do with it? what do you mean by "if I have to sign something ...and destroy the micro..." why would you destroy anything just because you had to sign something and what do you sing like a document?
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Wow! Thank you for your support.
Regarding the signing and destroying, its purpose is to cryptographic sign messages offline.
Once that message is signed, transfer it via camera imaging (qr code) to a online machine so that it can be broadcast.
Similar purpose as trezor and ledger .
Even if you use "shred" command, information is still recoverable via forensics, hence destroy a $5 sd drive.
All "Cloak and Dagger" stuff.
I just experiment and have fun.