The BitBoxApp allows you to sign a message with a Bitcoin address that was already used in your account. This can be useful when an exchange or another service asks you to prove that you control a specific address.
You can start this process from the View used addresses section in the BitBoxApp. After selecting the correct used address, the BitBoxApp opens the message signing screen with that address already preselected.
Before you begin
Make sure you have:
- The newest BitBoxApp installed
- Your BitBox02 set up, connected, and unlocked
- Access to the Bitcoin account that contains the used address
- The exact Bitcoin address you need to verify
- The exact message provided by the exchange or service
Exact address and message required
Use the exact address and message provided by the exchange or service. Even a small change in the message can make the signature invalid.
How to sign a message with a used address
The following example shows how to sign a message with a used Bitcoin address.
In this example, we use the following address:
tb1qaueaqg3nqtanqc074gzvpykgedwtede95gnyfhThis address was used in 2023.
- Open the BitBoxApp.
- Connect your BitBox02.
- Unlock your BitBox02.
- Select the Bitcoin account that contains the address you need to verify.
- Click Account information.
- Click View used addresses.
- Enter the address in the search bar.
- Check that the search result shows the correct address.
- If you do not find the address in Receive addresses, switch to Change addresses and search again.
Receive and change addresses
Receive addresses are addresses you shared to receive Bitcoin. Change addresses are created automatically by the BitBoxApp when Bitcoin change is returned to your wallet. Both can belong to your BitBox02 wallet.
- Click the matching address to expand its details.
- Click Sign message.
- Check that the address shown in the signing screen matches the address you need to verify.
- Enter the message you need to sign.
In this example, enter:
How to sign a used address.
- Click Sign on device.
- Confirm the message signing on your BitBox02.
- After the message was signed successfully, copy the address, message, and signature from the BitBoxApp.
In this example, the signed message details are:
Address:
tb1qaueaqg3nqtanqc074gzvpykgedwtede95gnyfh
Message:
How to sign a used address.
Signature:
H+YU23Gxj3CZEQ063K+U344/Ubasw66DYC07AC+QwsqsOhvHTGkZ6096Vrpvk/zA2R6WVUtpCSISBsKmQZaLEq0=
- Save or copy the signed message details.
- Click Done.
Message signed successfully
You have successfully signed a message with the selected used address. You can now provide the address, message, and signature to the exchange or service that requested the verification.
What to provide to the exchange or service
Most exchanges or services ask you to provide:
- The Bitcoin address
- The original message
- The generated signature
Copy and paste this information exactly as shown in the BitBoxApp. Do not edit the signature manually.
Do not change the signature
The signature must be copied exactly. If characters are changed, removed, or added, the exchange or service may not be able to verify it.
If you cannot find the address
If the address does not appear in the used addresses list:
- Check that you selected the correct Bitcoin account in the BitBoxApp.
- Search the address again in both Receive addresses and Change addresses.
- Make sure the address provided by the exchange or service was copied correctly.
- If you use multiple Bitcoin accounts, check the other accounts as well.
Account-specific address history
Used addresses are shown per Bitcoin account. If you use multiple Bitcoin accounts, each account has its own receive addresses, change addresses, and address history.
Important to know
Signing a message does not create a Bitcoin transaction. It does not move funds and does not expose your recovery words or private keys.
The signature only proves that your BitBox02 controls the private key for the selected address.
Message signing is not a transaction
Signing a message only creates cryptographic proof that you control the selected address. It does not send Bitcoin and does not change your wallet balance.
FAQ
Why would I need to sign a message with a used address?
You may need to sign a message when an exchange or service asks you to prove that you control a specific Bitcoin address. This is often used for address ownership verification.
Does signing a message send Bitcoin?
No. Signing a message does not create a Bitcoin transaction and does not send any funds. It only creates a signature that proves control over the selected address.
Can I sign a message with any Bitcoin address in the BitBoxApp?
You can sign a message with Bitcoin addresses that belong to your wallet and are available in the BitBoxApp. For this article, the focus is on addresses that already appear in View used addresses.
What if I cannot find the address?
Make sure you selected the correct Bitcoin account. Then search both Receive addresses and Change addresses. If you use multiple Bitcoin accounts, check each account separately.
Can a change address also be used to sign a message?
Yes. If the change address belongs to your BitBox02 wallet and appears in the used addresses list, you can sign a message with it.
Can I edit the message before signing it?
Only edit the message if the exchange or service allows it. If they provided a specific message, copy it exactly. A different message creates a different signature.
Can I edit the signature after signing?
No. Do not edit the signature. It must be copied exactly as shown in the BitBoxApp, otherwise the verification may fail.
Does signing a message reveal my recovery words or private keys?
No. Signing a message does not reveal your recovery words or private keys. The signature only proves that your wallet controls the private key for the selected address.