Feature request: sign and validate

[PMK]

Hello Phoenix/ACINQ

I would like to sign and verify a message using the static on-chain address of my wallet.

Some brokers require by law to sign a message using an on-chain address as their KYC policy. If done, I then can send fiat money directly to this wallet via this broker and Phoenix will add the liquidity to my lightning wallet. Signing a message from the broker once using the static on-chain address and validating a message is a feature I would like to use in Phoenix. Can this be implemented please?

Is there already a workaround to sign a message, like importing in Sparrow/Electrum?