MASTERING-BITCOIN · Unit 5 · Video 4
| Concept | What It Recovers | What Happens If Lost |
|---|---|---|
| Seed Phrase (BIP39) | Private keys via BIP32 derivation | You lose your coins entirely |
| Descriptor (BIP380) | Script type, cosigner xpubs, derivation paths | You can't locate complex (multisig) funds |
| Encrypted Wallet Backup | Labels, Lightning state, metadata, exchange history | Coins intact, but transaction history is blank |
| Derivation Path | Script Type | BIP |
|---|---|---|
m/44'/0'/0' |
Legacy P2PKH | BIP44 |
m/49'/0'/0' |
Nested SegWit | BIP49 |
m/84'/0'/0' |
Native SegWit | BIP84 |
m/86'/0'/0' |
Single-key Taproot | BIP86 |
The seed phrase is the root of a massive key tree. Each level branches into about 4 billion children. Your wallet's keys live on one specific path — but the seed itself doesn't tell you which one.
Use the slider to change the derivation path's purpose number and see how the tree fans out. Notice that only ONE thin branch is actually used by your wallet.
⚙ interactive visualization — coming to this page format soon
Reflect: The seed phrase does NOT record which path was used. If your new wallet scans m/84'/0'/0' but your old wallet used m/44'/0'/0', the balance will appear empty — the funds are there, on the blockchain, but on a branch the new wallet isn't looking at.
In a 2-of-3 multisig, the shared address is derived from ALL three cosigner public keys. Alice's seed gives her only her own key. Toggle what she has available and see whether she can locate or spend the funds.
⚙ interactive visualization — coming to this page format soon
Notice: Even with her full seed phrase, Alice cannot even find the shared UTXO without the other two cosigners' public keys. A seed phrase cannot encode someone else's public key — this is why multisig users need a descriptor as a separate backup artifact.
Explore what survives and what is lost under each failure scenario. Select which backup layer is lost and see the consequence.
⚙ interactive visualization — coming to this page format soon
Reflect: The severity of each loss is asymmetric. Losing the seed is catastrophic. Losing the descriptor means unreachable-but-existing funds. Losing the encrypted backup preserves your wealth but destroys your financial history.
Question 1
You restore a single-sig wallet from a 12-word BIP39 seed phrase. The correct balance appears. Which of the following will also be automatically recovered?
✅ Correct! A seed phrase is a deterministic source of private keys — nothing more.
❌ Not quite. Labels, Lightning state, and exchange rates all live in the wallet's local database and are not derived from the seed.
Solution:
The seed phrase is a deterministic source of private keys via BIP32 derivation. Given the same seed, you always get the same keys back — and therefore the same addresses.
Everything else lives in the wallet's local database and is not derived from the seed:
Only private keys and addresses come back from a seed-only restore.
Question 2
True or False: Two wallets that both implement BIP39 correctly will always display the same balance when given the same 12-word seed phrase.
✅ Correct! The seed alone doesn't specify the derivation path, so wallets using different implicit paths can miss funds.
❌ Not quite. BIP39 seeds carry no path information. A wallet scanning BIP44 paths will miss BIP84 funds.
Solution: False
BIP39 words carry no version information about which derivation path was used. Wallets rely on implicit conventions:
m/44'/0'/0' (Legacy)m/49'/0'/0' (Nested SegWit)m/84'/0'/0' (Native SegWit)m/86'/0'/0' (Taproot)If wallet A generated funds under BIP84 and you restore into wallet B that only scans BIP44, wallet B will silently show zero balance — even though the funds exist on-chain. The keys are derivable; the wallet just isn't looking in the right branch.
This is the "silent miss" problem: same seed, different paths, different visible balances.
Question 3
Alice participates in a 2-of-3 multisig with Bob and Carol. A disaster destroys Alice's laptop, but she still has her 24-word seed phrase engraved on steel. She has lost contact with Bob and Carol and has no backup of their public keys.
What is the status of Alice's share of the multisig funds?
✅ Correct! The multisig address itself is derived from all three pubkeys. Without the others, Alice can't even find the UTXOs on-chain.
❌ Not quite. In multisig, the address depends on the combined public keys of every cosigner. Alice's seed only gives her her own key.
Solution:
A multisig address is derived from all three cosigners' public keys combined via a witness script. The address on the blockchain is a hash of that script.
With only her own seed, Alice can derive only her own private key and public key. She cannot:
A seed phrase cannot encode someone else's public key — that would violate the whole point of individual key custody.
This is why multisig users need an output script descriptor (BIP380) as a separate backup. The descriptor bundles the script type, threshold, all cosigner xpubs, and derivation paths.
Additional note: even after Alice locates the funds via a descriptor, she still needs one more cosigner online to meet the 2-of-3 signing threshold before she can spend.
Question 4
A descriptor file containing your multisig's extended public keys (xpubs) is leaked to an attacker. The attacker has no access to any seed phrase or private key. What is the actual risk?
✅ Correct! xpubs reveal all addresses and balances, but private keys cannot be derived from them. It's a privacy loss, not a spending risk.
❌ Not quite. xpubs let an attacker derive all public addresses (and see balances) but not private keys. The risk is privacy, not theft.
Solution:
An extended public key (xpub) can derive all child public keys and therefore all receive and change addresses associated with the wallet. An attacker with the descriptor can:
However, they cannot spend:
So a leaked descriptor is a privacy disaster, not a theft risk. The guidance from the video: protect descriptors, but don't panic if one is exposed. Your coins are still safe; your transaction history is not.
Solved: 0 / 4