BA-04 · LESSON 09

Backups and recovery

KEY DEFINITIONS

Terms used in this lesson

BIP84: The wallet derivation convention for native SegWit single-key outputs.
xpub: A serialized extended public key containing a public key and chain code for deriving normal public descendants.
Descriptor: A machine-readable description of the scripts, keys, and derivation paths a Bitcoin wallet watches or can spend.
BIP39: A standard that converts entropy into mnemonic words and derives a seed using an optional passphrase.

Recovery requires more than seed words. A complete plan preserves every passphrase, key path, spending policy, and quorum rule needed to recreate and test the wallet.

35 min Difficulty 2/5 Not started

VISUAL MODEL

See the whole mechanism before going step by step

Use the diagrams to orient yourself. Then the guided explanation below teaches every part in depth.

4 explanatory views

CONCEPT-SPECIFIC MAP · backup coverageA backup is complete only if it restores every required secret and policySelect any state to inspect its exact role.

RELATIONSHIP MAPOrdered mechanism flow

01
SECRETMnemonic or signer backup
The backup must preserve the authorization material without exposing it to an online service.
02
PASSPHRASERecorded separately
A forgotten optional passphrase cannot be recovered from the mnemonic.
03
POLICYDescriptor or script setup
Multisig participants, paths, script types, and thresholds are not implied by the words alone.
04
TESTMatches known receive address
A non-destructive test proves the stored inputs reconstruct the intended wallet.
05
RESULTRecovery verified
Verification should happen before device loss, not during an emergency.

Rule shown: Test recovery with harmless data before funds depend on it, and keep the test separate from production secrets.

STAGE 1 OF 5SECRET: Mnemonic or signer backup

The backup must preserve the authorization material without exposing it to an online service.

Governing relationship: Test recovery with harmless data before funds depend on it, and keep the test separate from production secrets. Complete path: 1. SECRET, Mnemonic or signer backup. The backup must preserve the authorization material without exposing it to an online service. 2. PASSPHRASE, Recorded separately. A forgotten optional passphrase cannot be recovered from the mnemonic. 3. POLICY, Descriptor or script setup. Multisig participants, paths, script types, and thresholds are not implied by the words alone. 4. TEST, Matches known receive address. A non-destructive test proves the stored inputs reconstruct the intended wallet. 5. RESULT, Recovery verified. Verification should happen before device loss, not during an emergency.

1. State transitionWhat exists, what changes, and what results

BEFORE

A user has 12 BIP39 words for a multisig wallet but loses every device.

MECHANISM

List wallets, networks, output types, accounts, multisig cosigners, hardware devices, passphrases, and any timelocked or policy-specific paths.

AFTER

Backing up one secret is not the same as backing up the wallet system that uses it.

Text equivalent: Starting from A user has 12 BIP39 words for a multisig wallet but loses every device. The mechanism begins when List wallets, networks, output types, accounts, multisig cosigners, hardware devices, passphrases, and any timelocked or policy-specific paths. The resulting lesson is Backing up one secret is not the same as backing up the wallet system that uses it.

2. Mechanism pathSelect a stage to inspect its job

STAGE 1 OF 6

Inventory recoverable assets

List wallets, networks, output types, accounts, multisig cosigners, hardware devices, passphrases, and any timelocked or policy-specific paths.

Complete path: 1. Inventory recoverable assets: List wallets, networks, output types, accounts, multisig cosigners, hardware devices, passphrases, and any timelocked or policy-specific paths. 2. Back up secret material: Record seeds, key shares, or private keys with protection against theft, loss, fire, and single-location failure. Do not put all factors together without considering compromise. 3. Back up wallet metadata: Store descriptors, derivation and key-origin data, wallet creation height, labels if needed, and multisig participant information. 4. Document the recovery sequence: A future operator needs clear steps for obtaining software, verifying it, importing data, scanning the chain, and signing a safe test transaction. 5. Run a clean-room drill: On a separate or reset device, restore without using the original wallet, verify known addresses, and make a small test spend when safe. 6. Maintain and inherit: Update backups after policy changes, rehearse periodically, and provide access instructions that do not reveal secrets prematurely.

3. Rule and failure boundaryWhat accepts the result and where it can stop

ACCEPTED PATH

A recovery drill must match the concrete account xpub and BIP84 path, scan from a height covering a known output, satisfy quorum, reproduce its address, and execute a verified signature.

CHANGED CONDITION

A wrong descriptor, path, or late scan start misses discovery despite valid secrets, while one recovered signer cannot satisfy a 2-of-3 quorum.

Important distinction: A successful wallet-app import proves recovery is complete. The restored wallet must find expected outputs, reconstruct policy and change, and safely sign and broadcast. An empty but valid wallet may indicate a wrong passphrase or path.

Text equivalent: The accepted path is enforced by A recovery drill must match the concrete account xpub and BIP84 path, scan from a height covering a known output, satisfy quorum, reproduce its address, and execute a verified signature. If the required condition changes, A wrong descriptor, path, or late scan start misses discovery despite valid secrets, while one recovered signer cannot satisfy a 2-of-3 quorum.

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Learn the idea

A wallet backup must recover both authorization and discovery. Secret material may be a seed or individual keys. Discovery metadata includes output descriptors, key origins, derivation paths, accounts, and the address range to scan. A passphrase changes derived keys, and a recovery drill proves the recorded material actually works.

GUIDED EXPLANATION1/6 ideas inspected

Inventory recoverable assets

List wallets, networks, output types, accounts, multisig cosigners, hardware devices, passphrases, and any timelocked or policy-specific paths.

The worked example follows the explanation

Inspect every idea above to open it.

Important distinction“A successful wallet-app import proves recovery is complete.”

The restored wallet must find expected outputs, reconstruct policy and change, and safely sign and broadcast. An empty but valid wallet may indicate a wrong passphrase or path.

FINISH LEARNING FIRST

The questions unlock after every required learning activity

Inspect every guided idea, open the worked example, rebuild its mechanism, and complete the deterministic lesson tool. Your progress is saved automatically.