Bard spotting on Bluesky 20 November 2024

David Buchanan (@retr0.id):

Is there a way to

a) generate an ECDSA keypair

b) sign ONE message with said key

c) throw away the private key

d) publish msg+sig+pubkey

such that I can prove to other people that

a) I really did only sign a single message

b) I really did throw away the key after, and nobody can recover it

Ms. Penny Oaken, SkyWitch (@skywitches.net):

You'd need to prove chain of custody of the private key.

Which you could possibly do with a silicon enclave.

How to prove that the signed message & public key could only have originated from that enclave, though —

Have the enclave sign them &have the enclave configured to never disclose privkeys?

Ms. Penny Oaken, SkyWitch (@skywitches.net):

The closest practical answer is you would be asking people to trust a silicon enclave to generate a keypair, then sign a message, then output the required items, then destroy the privkey. It would have to be custom silicon.

Prove? Ugh I'm not that clever

Ms. Penny Oaken, SkyWitch (@skywitches.net):

So what you want is … silicon / an algo that, in the process of assembling your final output product, inherently destroys or overwrites the contents of memory that stored the privkey.

Which … involves somehow preventing readout of that memory outside the enclave before the operation finishes.