By the end, you’ll be able to…
- Explain a hierarchy of derived keys.
- Identify why derivation metadata and xpub privacy matter.
Three questions to carry into this lesson.
A tree replaces isolated key records
BIP 32 defines hierarchical deterministic wallets: a seed can derive a tree of keys through indexed paths. Extended keys include information needed for child derivation. This helps wallets create many receiving addresses without requiring a separately improvised backup for every new address. A path identifies a position in the hierarchy, not a separate blockchain account.
Public derivation is useful and sensitive
An extended public key can derive corresponding non-hardened public descendants without spending authority. That makes watch-only receiving and monitoring possible. It can also reveal a broad set of addresses and their activity. Some combinations of exposed extended public information and private descendants have serious security consequences, which is one reason hardened derivation exists.
Recovery needs context
A seed alone does not always tell replacement software which script type, account or path the original wallet used. Store the required policy metadata securely according to the wallet’s recovery design. Never post a real xpub in a public support issue merely because it cannot independently sign. For a learning diagram, label a root, account branch, receiving branch and change branch without including actual key material.
Practice on paper
A shop wants an online server to generate receiving addresses without holding spending keys. What concept helps, and what privacy tradeoff remains?
I’ve tried it — show the worked answer
A suitable extended public key or watch-only descriptor can support receiving-address generation. The server can still learn and expose the associated address history, so its scope and access should be limited.
Want to explore with buttons and instant feedback? Try the practice lab ↗
Make a choice. Discover why.
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One idea to take with you
Back up the policy context as well as the secret.
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