Yuragi 署名 — Offline Message Signer runs locally only
Sign a message with a BSV private key, entirely in this browser tab. Used to prove ownership of an address — e.g. claiming a Yuragi agent.
Before you paste a real private key: go offline.
This page makes zero network requests — no analytics, no fonts, no CDN, nothing fetched or sent anywhere. That's not just a promise: the Content-Security-Policy in this page's own <head> structurally blocks every outbound request a browser can make, so even a bug here has nowhere to send your key. Still — for anything beyond throwaway testing, the safest move is to download this file, then open it while disconnected from the internet (airplane mode / Wi-Fi off). A key that's signed offline never touches a network at all.
Saves this exact tool as one self-contained file. Open it later by double-clicking — no server, no internet connection required, ever.
1 — Your key
Derived address
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Don't have a key? Generate one offline.
Generates a fresh key using your browser's cryptographically secure random number generator. Nothing is transmitted. Write down the WIF somewhere safe — this page shows it exactly once and doesn't store it.