Create Digital Signature

WHAT IT DOES

Create Digital Signature enables you to create cryptographic digital signatures using your connected wallet's personal_sign method. Digital signatures are fundamental to blockchain security, allowing you to prove ownership of a wallet address without submitting an on-chain transaction. By signing a message, you demonstrate that you control the private key associated with your wallet address, enabling authentication, authorization, and verification use cases across Web3 applications. The tool takes a message (text or hex) and uses your wallet to generate an Ethereum-compatible signature. The signed message can be verified by anyone using standard Ethereum signature recovery methods, allowing off-chain verification of identity and intent. This is useful for logging into dApps, authorizing actions, proving ownership, and participating in token-gated experiences without spending gas.

HOW TO USE

Connect your wallet using the BGWallet connector. Select the message format: "Text" for plain text messages (the most common use case) or "Hex" if you need to sign raw hex data. Enter your message in the text area—this could be a login challenge, a statement of intent, a permission grant, or any other data you want to cryptographically attest to. The review panel displays the signer address, the selected format, and a preview of your message. After reviewing the message carefully, click "Sign message" to initiate the signature request in your wallet. Your wallet will display the message in a readable format for you to confirm before signing. Once you approve, the tool displays the resulting signature as a hex string. You can copy just the signature, or copy both the message and signature together for easy sharing with verifiers.

TECHNICAL MECHANISM

This tool implements the personal_sign standard (EIP-191) for signing messages with Ethereum wallets. When you click "Sign message", the tool uses ethers.js to call the wallet's signMessage() method, which internally uses the personal_sign RPC method. For text messages, the message is passed directly as a UTF-8 string. For hex messages, the tool validates that the string contains only valid hex characters and has an even length, then prefixes it with "0x" before signing. The wallet then hashes the message according to the personal_sign specification: it prepends the Ethereum signed message prefix ("\x19Ethereum Signed Message:\n" + message length) and hashes it with Keccak-256 before signing with the wallet's private key. The resulting signature is an ECDSA signature encoded as a 65-byte hex string (r, s, and v components), which can be recovered to the signer's address using ecrecover. This standard ensures compatibility with all major Ethereum wallets and verification libraries.

WHAT IT CANNOT SEE

This tool cannot verify that the signature will be accepted or understood by any specific verifier—the verifier must know the expected message format and content. It does not validate the message content or format beyond basic input validation; you are responsible for ensuring the message is correct. The tool cannot recover or modify the signature once signed; you must verify the message content carefully before approving. It does not automatically submit the signed message to any contract or service—you must use the signature in your own application logic. The tool cannot guarantee that the signing wallet supports personal_sign (though all modern wallets do). It does not support signing with specific derivation paths or non-standard signing methods beyond personal_sign. The tool cannot recover the signer's address from the signature without additional tools like ethers.js's verifyMessage() function. It does not support batch signing of multiple messages in a single operation.

PLEASE NOTE

This tool works with any EVM-compatible wallet that supports personal_sign, including MetaMask, WalletConnect, and most browser wallets. The signature produced can be verified using ethers.js's verifyMessage() function or the equivalent in other Web3 libraries. For text messages, the message is displayed in your wallet exactly as entered, so you should ensure the message clearly states what you are signing. For hex messages, your wallet may display the raw hex data without interpretation. The signature is unique to the message, signer address, and network context; the same message signed by the same wallet on a different network will produce a different signature due to the way the wallet personalizes the signing process. After signing, you can use the signature for off-chain verification, authentication tokens, or as proof of wallet ownership in various Web3 applications. Always sign messages only from trusted sources and applications.