You can use the BitBoxApp to generate a BIP-85 child key from the parent wallet currently loaded on your BitBox. The result is a separate set of 12 or 24 BIP-39 recovery words that you can restore in a compatible wallet.
This guide explains how to generate the child key and what you must record to recreate it. If you are still deciding whether to use BIP-85, first read What are BIP-85 child keys, and should you use them?
For an illustrated overview of the recovery model, derivation paths, and practical use cases, read One backup, infinite possibilities: BIP-85 child keys explained on the BitBox blog.
Before you begin
Prepare the following:
- The BitBoxApp, your BitBox, and the device password.
- The intended parent wallet loaded on the BitBox. If it uses an optional passphrase, enter the exact same passphrase.
- A private environment without cameras and an offline medium for recording the child recovery words.
- A planned word count, index, and purpose for the child key.
If Show BIP-85 child key is unavailable in the BitBoxApp, update the BitBoxApp and your BitBox firmware before continuing.
Confirm the parent wallet first
A missing or different optional passphrase opens a different parent wallet and produces different child recovery words. Make sure the intended parent wallet is loaded before you generate the child key.
Generate a BIP-85 child key
- Open the BitBoxApp.
- Connect and unlock your BitBox. Make sure the intended parent wallet is loaded. If it uses an optional passphrase, enter the exact passphrase.
- In the BitBoxApp, go to Settings → Expert settings and select Show BIP-85 child key.
- Read the explanation in the BitBoxApp and continue. On your BitBox, confirm Derive BIP-39 mnemonic?
- Choose 12 words or 24 words, enter the intended index, and verify the displayed keypath on your BitBox before confirming. Record the word count, index, and purpose.
Keep child recovery words offline
Do not photograph, scan, copy, or type the words into a computer, phone, website, browser extension, password manager, cloud service, or AI tool. Only enter them when you deliberately restore the child wallet in a trusted, compatible wallet.
- Write down every recovery word exactly as shown on your BitBox. Keep the words offline and preserve their order.
- Before leaving the workflow, compare the complete 12- or 24-word sequence with your BitBox.
- Store the child recovery words securely. Separately document the word count, index, purpose, and whether the parent wallet uses an optional passphrase.
Child key generated
You are finished when all 12 or 24 recovery words are recorded in order and the word count, index, purpose, and parent-wallet passphrase status are documented.
Use the child key in a compatible wallet
The child recovery words are standard BIP-39 recovery words. You can restore them using:
- Another BitBox: Restore the recovery words directly on the device to keep the child wallet in a hardware-wallet workflow. Follow How to restore your wallet using recovery words.
- A compatible software wallet: For a Bitcoin child wallet, trusted examples include Sparrow Wallet and Electrum. Use the wallet's BIP-39 import or restoration option; in Electrum, select the BIP-39 seed option during restoration.
Entering the recovery words into software on a computer or phone turns the child wallet into a hot wallet, so its security depends on that device. Use a software wallet only when this tradeoff fits the child wallet's purpose and value. Always follow the wallet's official recovery instructions and verify the wallet details before receiving funds.
How to recreate the same child key
To recreate the same child key from the parent wallet, you need:
- The same parent-wallet backup.
- The exact optional passphrase, if the parent wallet uses one.
- The same word count.
- The same index.
Repeat the generation steps and verify the keypath and recovery words on the BitBox. A different parent wallet, optional passphrase, word count, or index produces a different child key.
BitBox Support cannot recover missing child recovery words, an unknown optional passphrase, or a forgotten index.