A "Satoshi Test," sometimes called a "UTXO proof" or "address ownership proof," is a method for verifying that you have control over a specific Bitcoin address. It involves sending a tiny, precise amount of Bitcoin from that exact address as instructed by a third party, like a cryptocurrency exchange.

This guide provides start-to-finish instructions on how to perform a Satoshi Test using your BitBox hardware wallet and the BitBoxApp.

Before you begin: Preparation is key

To ensure the test succeeds on the first try, you must prepare your wallet and understand the requirements.

Make sure the address has funds

The most common reason a Satoshi Test fails is because the specific Bitcoin address you need to prove ownership of is empty. An address must hold a UTXO (Unspent Transaction Output) to be selectable in the BitBoxApp.

• How to check: If you cannot find the address you need to verify within the BitBoxApp's "Coin Control" feature (see next steps), it's likely because it holds no funds. You can confirm this by copying your address and pasting it into a block explorer like mempool.space.
• Solution: If the address is empty, you first need to send a small amount of Bitcoin to that specific address. This transaction will create a UTXO, making the address "active" and ready for the test. The amount you send must be large enough to cover both the small test amount and the future network transaction fee.

Enable Coin Control

This test requires sending funds from one specific address, which is not standard wallet behavior. You must enable the "Coin Control" feature to do this.

1. In the BitBoxApp, navigate to Settings > Advanced settings.
2. Toggle the switch to turn on Enable coin control.

Review the exchange's instructions

Carefully read the instructions provided by the exchange or service that requires the verification.  Pay close attention to two things:

• The exact destination address they want you to send to.
• The precise amount of BTC they require for the test.

Sending the wrong amount or to the wrong address will cause the test to fail.

Performing the Satoshi Test: Step-by-step

Once you have funded the correct address and enabled Coin Control, follow these steps to execute the transaction.

Step 1: Open the Coin Control panel

1. In the BitBoxApp, select the correct Bitcoin account where the address is located.
2. Click on Send.
3. On the sending screen, click the Coin control button on the right side. This will open a list of all your UTXOs for that account.

For more details on how to use Coin Control, see our full guide: What is Coin Control and how do I use it?

Step 2: Select the correct UTXO

This is the most critical step. From the list, find and select the UTXO that corresponds to the exact Bitcoin address you need to verify.

Important: Avoid UTXOs from “Change Addresses”

While a test from a change address might technically work (it's still an address you control), it's not recommended.

Change addresses are internal addresses automatically generated by the BitBoxApp for transaction "leftovers." They don't typically appear in your standard transaction history, only in Coin Control, where they are marked as a “change address.”

Using a change address can cause confusion in tracking the test payment. Always aim to use a UTXO from the primary, visible address your exchange expects.

 

Step 3: Enter transaction details

Carefully enter the recipient address and the exact BTC amount that the exchange provided in their instructions.  Double-check that these values are perfect.

Step 4: Verify and confirm on your BitBox

Finally, review all details (recipient address, amount, fee) on the BitBoxApp screen. Then, perform the final security check by verifying the exact same details on your BitBox02's trusted display. If everything matches, confirm the transaction on the hardware device. 

Troubleshooting common issues

If the exchange doesn't verify your address after the transaction has been confirmed on the blockchain, check these common reasons.

• Incorrect UTXO selected: You may have accidentally sent funds from a different address or a change address. The solution is to perform a new test, ensuring you select the UTXO for the correct receiving address.
• Incorrect amount or recipient: The amount sent or the recipient address did not exactly match what the exchange required. You will need to perform the test again with the correct details.
• Network congestion: The transaction may be stuck or unconfirmed due to high network traffic.  You can check its status on a block explorer. If it's unconfirmed, you may need to wait longer.

If you have checked everything and still have issues, please contact the exchange's support team for further assistance.