If you need to set up a new BitBox02 or restore an existing one after a factory reset, your recovery words are the key. These words act as the master backup for your cryptocurrency wallet, allowing you to regain access to all your accounts and funds.

Understanding recovery words (BIP39)

The BitBox02 uses a standard called BIP39 to generate and manage your recovery words (also known as a mnemonic phrase or seed phrase). This phrase can be 12, 18, or 24 words long. These words are used to create the secret keys that control your crypto.

The number of words relates directly to the security level (entropy) of your backup:

• 12 words: 128 bits of entropy
• 18 words: 192 bits of entropy
• 24 words: 256 bits of entropy

More words mean a higher level of security because the combination is harder to guess. You can find the technical details in the official BIP39 specification on GitHub. 

Critical security precautions

Your recovery words are your crypto. Treat them with extreme care:

• Keep them secret: Never share your recovery words with anyone, under any circumstances. Anyone who has them can steal your funds.
• Keep them offline: Do not store your words digitally. This means no photos, no cloud storage, no password managers, no emails, no text files. Use physical backups like the BitBox backup card or a Steelwallet.
• Handle them privately: When you need to access your words (like during restoration), make sure you are in a secure, private location. Do not say the words out loud.

Steps to restore your wallet

Follow these steps carefully using the BitBoxApp and your BitBox02 device:

1. Prepare your BitBox02: Ensure you are using a new or factory-reset BitBox02.
2. Install the BitBoxApp: If you haven't already, download and install the BitBoxApp from the official source: bitbox.swiss/download/ 
3. Connect and pair: Plug your BitBox02 into your computer or Android phone. Open the BitBoxApp and follow the pairing instructions shown on your computer screen and the BitBox02 device.
4. Start restoration: When prompted to set up the BitBox02, choose the option "Restore from recovery words".
5. Select word count: Choose whether your backup uses 12, 18, or 24 words.
6. Enter recovery words: Using the touch sensors on your BitBox02, carefully enter each recovery word in the correct sequence. The device will guide you.
7. Set device password: Create a strong, unique password for your BitBox02. This password protects your device from unauthorized physical access.
8. Complete: After confirming the words and setting the password, the BitBoxApp will synchronize your accounts. Your wallet is now restored!

Using an optional passphrase (25th word)

If your original wallet setup included an optional passphrase (sometimes called the 25th word), you must enable this feature again in the BitBoxApp after the initial restoration process described above.

• During restoration: The process above only restores the wallet derived from the 12, 18, or 24 words. It does not prompt for the passphrase.
• After restoration: Go to Device settings in the BitBoxApp and activate the Optional passphrase feature. You will then be prompted to enter your specific passphrase on the BitBox02 device to access the passphrase-protected wallet.

Restoring the main seed words only gives access to the wallet without the passphrase. The passphrase-protected wallet is separate and requires this extra step. Understand the trade-offs in our blog post: Optional passphrases: benefits and risks. 

Important note on Bitcoin address types

The BitBoxApp and BitBox02 fully support modern Bitcoin address formats like SegWit (addresses starting with 3) and Native SegWit (addresses starting with bc1) for both sending and receiving.

However, the BitBoxApp does not generate or display receive addresses in the older Legacy format (starting with 1). This means:

• If the recovery words you are restoring have funds associated with Legacy addresses from a previous wallet, these specific balances will not appear in the BitBoxApp.
• You can still send Bitcoin from your BitBox02 (from your SegWit or Native SegWit accounts) to an external Legacy address if necessary.

Learn more: Understand the differences in our blog post: What are Bitcoin address types? 

Security considerations for imported wallets

When you restore a wallet using recovery words generated by another wallet application or device, the security of your funds depends on how securely those words were originally generated and stored.

After restoration: Check your backup

• If backup is secure: If you are certain your recovery words were never lost, stolen, or digitally exposed, store your physical backup securely again.
• If backup might be compromised: If there's any chance your recovery words were seen by someone else, photographed, or stored digitally, consider them compromised. Immediately create a completely new wallet on your BitBox02 (generating new words) and transfer all your funds to the new wallet's addresses. Discard the compromised recovery words.