When generating BIP-85 child keys using your BitBox02 hardware wallet, it's essential to understand the key parameters involved: the number of words, the index number, and the keypath. These settings determine the uniqueness and recoverability of each child wallet derived from your master seed.
Number of words
This parameter specifies the length of the mnemonic phrase for the child wallet. You can choose between 12, 18, or 24 words. The number of words affects the entropy and security level of the generated wallet. For instance, a 24-word phrase offers higher entropy than a 12-word phrase, providing enhanced security.
Index number
The index number is a non-negative integer (e.g., 0, 1, 2, ...) that differentiates each child wallet derived from the master seed. Using the same index number with the same word count will always generate the same child wallet. It's crucial to keep a record of the index numbers you use, as they are necessary for regenerating specific child wallets in the future.
Keypath
The keypath defines the derivation path used to generate the child key. In BIP-85, the standard keypath format is:
m/83696968'/39'/0'/index'
-
mdenotes the master node. -
83696968'is the purpose code for BIP-85. -
39'indicates the application type (e.g., BIP-39 mnemonic). -
0'is a fixed parameter for BIP-39 mnemonics. -
index'is the index number you choose.
This standardized keypath ensures that each child key is uniquely derived and can be consistently regenerated using the same parameters.
Best practices
- Consistent Documentation: Keep a secure record of the parameters used for each child wallet, including the word count and index number. This practice ensures you can accurately regenerate any child wallet when needed.
- Secure Storage: While child wallets can be regenerated, it's still advisable to store their mnemonic phrases securely, especially if they are actively used.
- Avoid Reuse: Do not reuse index numbers for different purposes to prevent confusion and potential security risks.
Understanding these parameters allows you to effectively manage multiple wallets derived from a single master seed, enhancing both security and convenience.