Key management · The 10-minute crash course

Private keys & seed phrases

A seed phrase is a human-readable backup of every key in your wallet. Treat it the way you'd treat a stack of cash equal to your entire net worth — because that's what it is.

Open sourceNon-custodialNo KYC
Seed length
12 words
BIP-39 standard
Word list
2,048
fixed dictionary
Entropy
128-bit
uncrackable by brute force
Cloud copies
0
if you do it right
01

What a seed phrase actually is

When Lightning Pay creates a wallet, it generates 12 random words from a fixed list of 2,048. Those words encode a 128-bit master secret, from which every Bitcoin address and private key in your wallet is derived deterministically.

Restore the same 12 words on any BIP-39-compatible wallet — Lightning Pay, Sparrow, Electrum, hardware wallets — and the same addresses reappear with the same balances. The blockchain is the same; only the key changes hands.

Standard
BIP-39 (Bitcoin Improvement Proposal 39)
Word list size
2,048 carefully chosen English words
Entropy
128 bits — would take the entire Bitcoin mining network billions of years to brute-force
Compatible wallets
Lightning Pay, Sparrow, Electrum, BlueWallet, Phoenix, Ledger, Trezor, Coldcard, and more
Optional
BIP-39 passphrase — a 13th word only you know, for an extra layer
02

Do — the right way to back up

  1. 1

    Write the words on paper

    Use a pen, not pencil. Number each word. Double-check the spelling against the BIP-39 list (Lightning Pay shows it during backup).
  2. 2

    Make two copies in two physical locations

    One at home, one in a safe-deposit box or a trusted family member's house. Single-location backups are one fire away from total loss.
  3. 3

    Upgrade to steel for serious balances

    Once you're past ~$10k, use a steel plate (Cryptosteel, Coldbit, Steelwallet). Paper survives most things; steel survives all of them.
  4. 4

    Use a tamper-evident envelope

    So you'd notice if a curious roommate ever opened it.
  5. 5

    Test recovery before depositing real money

    Wipe the wallet, restore from the seed, confirm the receive address matches. Two minutes of paranoia saves a lifetime of regret.
03

Don't — the digital backups that kill people

A seed phrase that touched the internet is a compromised seed phrase
Treat any digital copy as already-leaked. The threat isn't always today's hacker — it's the breach four years from now of a service that backed up your iCloud notes.
Where seed phrases get stolen, in order of frequency
Storage locationRiskWhy it fails
Screenshot in Photos / iCloudCriticalSynced to every device; one Apple ID phish empties the wallet
Google Drive / Dropbox docCriticalAny account breach or shared-folder mistake exposes it
Notes / Evernote / ObsidianCriticalSynced to cloud by default; encryption is often opt-in
Email to yourselfCriticalEmail provider owns the data; subpoenable; phishable
Password manager (encrypted vault)HighBetter than the above, but LastPass-style breaches happen — and a single master password becomes catastrophic
Plain paper in one drawerMediumFire, flood, theft, or a moving box solves you out of your savings
Paper + steel in two physical locationsLowIndustry standard for serious holders
Multisig across hardware walletsVery lowRequires multiple devices in multiple places to be compromised simultaneously
04

Mistakes that drain wallets

  • Typing the seed into a website. No legitimate wallet, exchange, or support team will ever ask. If a page asks, it's a phish — close the tab.
  • Sharing with "support." Real support never needs your seed. The DM from "Lightning Pay support" on Telegram is always an attacker.
  • Saving "just in case" digital copies. The temporary screenshot you take while transcribing? Delete it. The Drive doc you'll move to paper "later"? You won't.
  • Buying a pre-loaded hardware wallet on Amazon. Only buy direct from the manufacturer. A pre-set seed is an attacker's seed.
  • Memorising and skipping the paper. Brain wallets fail. Memory fades. Use paper plus a redundant copy.
05

Advanced: passphrase, multisig, and hardware

BIP-39 passphrase

An optional 13th word only you know. Even if someone steals your 12-word seed, they can't spend without it. Adds an enormous layer for minimal effort.

Multisig (2-of-3, 3-of-5)

Require multiple keys in multiple locations to authorise a spend. The gold standard for $100k+ balances. Lightning Pay supports multisig via Sparrow/Specter coordination.

Hardware wallet

Ledger, Trezor, Coldcard — the seed never leaves the device. Pairs with Lightning Pay for an air-gapped signing flow on every transaction.

Time-locked recovery

Advanced setups can enforce a cooling-off period (e.g. a stolen key can't move funds for 30 days, giving you time to react).
06

What to do if you've already lost / compromised your seed

If your seed phrase was photographed, uploaded, emailed, or seen by someone else

Move the coins. Now.

Generate a brand-new wallet, write down its fresh seed phrase on paper, and send every sat from the old wallet to a new address from the new wallet. The compromised seed is permanently burned — never reuse it.
  1. Open Lightning Pay → Settings → Create a new wallet.
  2. Back up the fresh 12-word seed on paper.
  3. Send your entire balance from the old wallet to a fresh address in the new wallet.
  4. Verify the transfer, then archive (or shred) the compromised seed.
07

Private key & seed-phrase FAQ

Ready to own your Bitcoin?

Lightning Pay is free, open source, and non-custodial. Your keys never leave your device.

Download Lightning Pay