Signature Signer & Verifier
Sign messages with a private key and verify Ethereum EIP-191 signatures. Recover signer addresses from signed messages.
This tool runs entirely in your browser. Never enter private keys that control real funds.
About EIP-191 Signed Messages
- Ethereum personal signatures use the EIP-191 standard, which prefixes the message with
"\x19Ethereum Signed Message:\n" + message.lengthbefore hashing with Keccak256. - This prefix prevents signed messages from being used as valid transactions.
- The signature is 65 bytes: r (32 bytes) + s (32 bytes) + v (1 byte).
vis typically 27 or 28 (0x1b or 0x1c).
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