signmessagewithprivkey "privkey" "message" Sign a message with the private key of an address Arguments: 1. privkey (string, required) The private key to sign the message with. 2. message (string, required) The message to create a signature of. Result: "str" (string) The signature of the message encoded in base 64 Examples: Create the signature > bitcoin-cli signmessagewithprivkey "privkey" "my message" Verify the signature > bitcoin-cli verifymessage "1D1ZrZNe3JUo7ZycKEYQQiQAWd9y54F4XX" "signature" "my message" As a JSON-RPC call > curl --user myusername --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "signmessagewithprivkey", "params": ["privkey", "my message"]}' -H 'content-type: text/plain;' http://127.0.0.1:8332/