Hi,I realized that there isn't any way to ask for a signature (or to verify a message) as easily you can do when requesting a payment using a bitcoin URI scheme (BIP0021).I think a URI scheme to use the signing tools in bitcoin core might be useful, and with a proper consensus it could become available in most bitcoin clients who already support message signing/verifying and payment url (or QRCode) and enable new uses of bitcoin signatures.A way to gain proper consensus is going through a BIP, so that's why I'm here: to present my idea publicly before going any further (draft BIP and reference implementation).Some thoughts - like BIP0021: "Bitcoin clients MUST NOT act on URIs without getting the user's authorization." so signing requires the user to manually approve the process - it could use the same URI scheme than BIP0021 with an additional parameter (ex: signaction=) or use another one like BIP121 (ex: btcsig:)PS : I'll also post a topic in "Development & Technical Discussion" section on Bitcointalk
 --Arthur Bouquet