This guide shows you how to perform a "Satoshi Test" to prove you control a specific Bitcoin address. This is often required by exchanges and involves sending a precise, small amount of bitcoin from that address. Using the Coin Control feature is the easiest way to do this.
Before you start
- The address must contain funds: To select a coin from an address, it must have a UTXO. If the address has a zero balance, you will first need to send a small amount of bitcoin to it.
- Enable coin control: You must first activate the feature in the settings.
- Get the exact details: Your exchange or service will provide you with the precise recipient address and the exact BTC amount you need to send. Have these ready.
How to perform a Satoshi test
Follow these steps carefully to ensure your test is successful.
- From your Bitcoin account, click the Send button.
- Click the Toggle coin control button to open the list of your UTXOs.
- Carefully review the list and select the single UTXO that is associated with the address you need to verify. Do not select UTXOs from "Change" addresses unless specifically instructed to.
- Enter the exact recipient address and BTC amount provided in the test instructions. Double-check that these values are perfect.
- Review all details (recipient address, amount, fee) in the BitBoxApp summary.
- 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
If the exchange doesn't verify your address after the transaction is confirmed, it's usually for one of these reasons.
You selected the wrong coin, or the address is now empty
You may have accidentally sent funds from a different address. You will need to perform a new test, making sure to select the UTXO for the correct address.
A common point of confusion is that after you spend from an address, it often becomes empty and disappears from the coin control list. This is normal Bitcoin behavior due to the UTXO model.
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How the UTXO Model Works:
- Think of your Bitcoin balance as cash in your wallet. Instead of a single balance, you have individual bills and coins (e.g., a $20 bill, a $5 bill, and three $1 coins).
- These are your UTXOs. If you need to pay for something that costs $2, you can't just tear off a piece of the $20 bill.
- You have to give the whole $20 bill (the UTXO) and you get $18 back as new change (a new UTXO), which your wallet stores in a new "change" address.
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Why the Address is Now Empty:
- When you performed the Satoshi test, you "spent" the entire UTXO associated with that address.
- The small test amount went to the exchange, and the rest of the funds (the change) were sent to a new change address in your wallet.
- The original address is now empty and therefore no longer has a UTXO to select in the coin control screen.
You entered the wrong details
The amount sent or the recipient address did not exactly match what the exchange required. You must perform the test again using the precise details they provided.
The transaction is stuck
Due to high network traffic, your transaction may be unconfirmed. You can check its status on a block explorer like mempool.space. Usually, you just need to wait longer for it to be confirmed by miners.
Frequently asked questions
I can't find the address I need to verify. Where is it?
If you cannot find the address within the BitBoxApp's Coin Control list, it's likely because it holds no funds (UTXOs). You can confirm this by copying your address and pasting it into a block explorer like mempool.space.
Why is the exchange asking me to do this?
Exchanges and other services use this test as a security measure to verify that you are the legitimate owner of an external wallet address before they allow you to withdraw funds to it. Because only the owner of the private keys can create a transaction from that address, it serves as cryptographic proof of ownership.
Is there a better way to prove I own an address?
Yes. A superior method is to sign a message with your address. This provides the same proof of ownership without requiring you to send a transaction, so it is faster and does not cost any network fees. Ask your exchange if they support "address signing" or "message signing" for verification. You can learn more about why this is a better standard.
The test still isn't working. What should I do?
If you have checked all the troubleshooting steps and the exchange still won't accept the test, contact the exchange's support team first. If you continue to have issues, you can contact us in support with the following details:
- The name of the exchange
- The Bitcoin address you are trying to verify