Sign a message using your node
lnd
lncli signmessage "message to sign here"
core-lightning
lightning-cli signmessage "message to sign here"
eclair
eclair-cli signmessage --msg=$(echo -n 'message to sign here' | base64)
Ride The Lightning
Navigate to Lightning > Sign/Verify > Copy
Thunderhub
Navigate to Tools > Sign message > Copy