Bitcoin message signing is built into the BitBoxApp for both new and previously used addresses. You do not need to install Electrum to sign a message with your BitBox02. Follow How to sign a Bitcoin message in the BitBoxApp to use this built-in feature.
If you prefer to use Electrum, this guide shows you how to sign the service's message with the requested address, verify the signature, and submit the result. Signing a message does not send bitcoin or incur a network fee, and your private keys remain on the BitBox02.
A valid signature proves control of the selected address. It does not prove your identity, legal ownership of funds, or control of other addresses. The requesting service decides which address types and signing formats it accepts.
Before you begin
- Use Electrum on your computer, downloaded from the official Electrum website.
- Your BitBox02 must already be set up, with its firmware updated through the BitBoxApp. Close the BitBoxApp completely before using Electrum so it does not occupy the device connection.
- Have the exact address and complete message supplied by the requesting service ready. Create your own message only if the service explicitly asks you to.
- Open the Electrum wallet connected to the BitBox02 account containing that address. If you have not connected it yet, follow How to connect your BitBox02 with Electrum. A wallet imported only for watching cannot sign through your BitBox02.
This procedure supports Bitcoin mainnet addresses in a single-signature wallet using Native SegWit (bc1q) or wrapped SegWit (3). It does not support Taproot (bc1p), legacy (1), multisignature wallets, or test networks. An address prefix alone does not establish compatibility: the address must belong to the supported account connected to your BitBox02.
Check what you are being asked to sign
Sign only a message you understand and expected to receive from the intended service. If the request is unclear or asks for recovery words, private keys, passwords, an optional passphrase, or a wallet backup, stop. None of these secrets is needed to prove address control.
Sign and verify the message
Use the wallet for the account containing the requested address. Each Electrum wallet connected to your BitBox02 represents its selected account and address type; it does not automatically include every account in the BitBoxApp. The screenshots below are examples: use your own requested address and message.
- In Electrum, open the Addresses tab. If it is hidden, select View → Addresses from the menu bar. The tab lists addresses in the selected wallet.
- Find the exact requested address, checking receiving and change addresses as needed. Right-click that address and select Sign/verify message. The signing window opens with the address filled in. If you cannot find it, use the troubleshooting guidance below rather than choosing a different address.
- Check the complete Address field against the service's request, then paste the supplied message into the Message field. Preserve its capitalization, punctuation, spaces, and line breaks.
- Select Sign. Connect and unlock your BitBox02 if prompted; the device asks you to review the signing request.
- On the BitBox02 display, review the complete address and message. Confirm on the device only if both match the original request exactly. Reject the request if either differs or you do not understand it. After confirmation, Electrum fills the Signature field.
- Select Verify in the same window. Electrum displays Signature verified when the signature is valid for the address and message in the window. If verification fails, resolve it before submitting the result.
Share the signed result
Copy the address, original message, and generated signature from Electrum and submit them through the requesting service's designated form or channel. Keep all three unchanged. Share the proof only with the intended recipient because it can associate you with that Bitcoin address.
Signature verified confirms that the signature is valid for the address and message you checked. The service must still verify your submission and confirm that it meets its requirements.
If something does not work
The requested address is not listed
Check that you opened the Electrum wallet connected to the correct BitBox02 account and address type, including the intended optional-passphrase wallet if you use one. Look through both receiving and change addresses. If you need to connect another account, use the account-selection guidance in the connection guide linked above. Do not substitute another address when the service requires a specific one.
Signing is unavailable or the address type is unsupported
If Sign/verify message is missing from the address menu, check whether you opened a watch-only or multisignature wallet. Use the wallet connected directly to your BitBox02 for the supported single-signature account. Do not import recovery words or private keys into Electrum to enable signing.
If Electrum reports that the address type is unsupported, ask the requesting service which compatible address and signing format it accepts before trying another method.
Electrum does not detect the BitBox02
Close the BitBoxApp and any other application using the device, reconnect and unlock your BitBox02, and try again. If detection still fails, follow the connection guide linked above.
Verification fails in Electrum
If Electrum displays Wrong signature, check that the address, message, and signature have not changed. Compare the message with the original request, including spaces and line breaks. If you correct the message or address, sign it again and verify the new signature.
The service rejects a verified signature
If Electrum displays Signature verified but the service rejects your submission, check that you submitted the same three values. If they are unchanged, ask the service whether it accepts the address type and Electrum's signing format. A valid signature does not guarantee that the service accepts it.