Message signing is a way you can prove you control a particular address, and demonstrate you have ownership.

You will need:

• Compatible wallet client
• Use Bitcoin’s original single-signature P2PKH address (address with prefix 1). Verification service is not compatible with Segregated Witness, or SegWit (address with prefix 3)
• Ability to generate new wallet addresses
• Support message signing

Verification service uses the verifymessage RPC command to verify a signed message.