Sign a message with a Bitcoin, Ethereum, Solana, Ripple (XRP Ledger) or Cardano wallet, then verify the signature in your browser. A cryptographic proof of ownership — no server, no transaction, no fee.
Sign a message
The message is signed byte for byte. Spaces, line breaks and trailing newlines are part of the signature and are never trimmed.
Signed
- Address
-
- Message
- Signature
-
The shareable link carries the proof in the URL fragment, so it is never sent to any server. Anyone who opens it can re-check the signature themselves.
Verify a signature
Paste the message exactly as it was signed — whitespace included.
How it works
Signing proves control
Your wallet signs the message with your private key. The key never leaves the wallet — the site only receives the resulting signature. Nothing is broadcast to a blockchain, so there is no gas fee and no transaction.
Verification is pure maths
Checking a signature needs only the address, the message and the signature. It happens in your browser with no wallet connection and no network request, so you can verify a proof offline or from a downloaded copy of this page.
Nothing is stored
There is no backend, no database and no analytics. Shareable links keep the proof in the URL fragment, which browsers never transmit to a server.
Why it matters
Regulation
Proving control of a wallet is now a regulatory requirement, not a technical curiosity. In the EU, MiCA sets the licensing framework for crypto-asset service providers, while the Transfer of Funds Regulation governs what happens when those providers deal with self-hosted wallets — requiring verification of customer control for transfers above €1,000. Comparable rules apply in over 70 jurisdictions under FATF Recommendation 16.
Compliance
If an exchange has ever asked you to prove you own an address before releasing a withdrawal, this is what they meant. The requirement applies to deposits and withdrawals alike, and a cryptographic ownership proof is one of the accepted methods.
Independence
Signing a message is entirely off-chain: no transaction, no network fee, no funds in motion — unlike a test transfer, which costs money, takes time, and leaves a permanent public trace. You prove control of the key without ever exposing it, and without waiting for a block.