signmessage

[LeoComandini]

There are a few issues/open points with Elements/Liquid signmessage and verifymessage

• Elements Core uses the same prefix as Bitcoin
• During verification the blinding key is ignored
• Verification only works for p2pkh, see signmessage and signmessagewithprivkey don't work unless the address you use is of type legacy #976

Are we ok with all of the above? or do we we want to change something?

Do we still want to support message signing in Core?

Do we want to extend message signing and verification to non-p2pkh? Do we want to do it outside Core?

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FWIW, here is a summary of what some existing wallets implement

			Core	GDK	Electrum
signmessage	bitcoin	p2pkh	✅	✅	✅
signmessage	bitcoin	p2sh-p2wpkh	❌	✅	✅
signmessage	bitcoin	p2wpkh	❌	✅	✅
verifymessage	bitcoin	p2pkh	✅	❌	✅
verifymessage	bitcoin	p2sh-p2wpkh	❌	❌	✅
verifymessage	bitcoin	p2wpkh	❌	❌	✅
signmessage	liquid	p2pkh	✅	❌	❌
signmessage	liquid	p2sh-p2wpkh	❌	❌	❌
signmessage	liquid	p2wpkh	❌	❌	❌
verifymessage	liquid	p2pkh	✅	❌	❌
verifymessage	liquid	p2sh-p2wpkh	❌	❌	❌
verifymessage	liquid	p2wpkh	❌	❌	❌

Electrum was included in the above table since it was used as a reference to add support for non-p2pkh signing to GDK.

[jmastr]

@LeoComandini Thank you so much for kick starting the discussion here and putting in the effort to create this table. Highly appreciated.