how to sign a bitcoin message - bitcoin signature

https://steemit.com/bitcoin/@bitsignal/how-to-sign-a-bitcoin-message-using-your-private-key

I used the following github tool to sign the message: https://github.com/ReinProject/bitcoin-signature-tool

From: blocksize

Bitcoin Signature Tool for Decentralized Services Market

This video shows how easy it is to paste, verify, and sign a message using an ECDSA private key behind a Bitcoin address.

From: David Sterry