Back to your message,
Hello NotATether.
This was my first
bitcointalk post. I was trying to recover some altcoin airdrop for bitcoin holders and I needed to sign a message. Then I discovered it was not possible.
By the time, in 2018, nullius gave me some technical details about the problems for creating this standard.
Take a look, it might help you:
...
A lot of good links in that mailing list thread, but I think this one is going to be the most helpful -
https://github.com/brianddk/bips/blob/legacysignverify/bip-0xyz.mediawiki . I'll study this draft BIP and see what I can get from it.
OK, so I apparently forgot that Taproot addresses do not even use ECDSA signatures in the first place. So I'm going to rule those out of the BIP.
According to @achow101, guessing the signature type from the prefix still makes ambiguous address types, so I'll have to figure out a different strategy to identify P2WPKH-P2SH and P2WPKH (P2SH and P2WSH have already been stiken out of this BIP).