Seed Phrase
Definition
A seed phrase (also called recovery phrase, mnemonic phrase, or backup phrase) is a standardized set of 12 or 24 words that can regenerate all private keys for a cryptocurrency wallet. It is the master backup of your wallet — not stored by anyone else, your sole responsibility.
How It Works
Seed phrases follow the BIP-39 standard (for most wallets). The wallet generates a random number called entropy, converts it to a sequence of words from a fixed 2,048-word list, and encodes it as your recovery phrase.
From this phrase, your wallet derives every private key for every address you use.
Critical Security Properties
- Complete access: Anyone with the seed phrase has full control of all funds in the wallet
- Unchangeable: Cannot be changed — only a new wallet with a new seed phrase provides a fresh start
- Non-recoverable without it: If you lose your seed phrase and your hardware wallet, your funds are permanently inaccessible
- No third-party storage: No company, exchange, or service should ever have your seed phrase
Storage Best Practices
- Metal backup: Engrave or stamp on metal plates (fire and water resistant). Products: Cryptosteel, Billfodl.
- Geographic distribution: One copy at home, one at a separate secure location (safe deposit box, trusted relative).
- Never digital: No photos, no cloud storage, no password managers, no screenshots.
- Estate planning: Include seed phrase recovery in your estate plan with clear legal instructions.
Related
- [Self-Custody](/guides/bitcoin-self-custody-tradeoffs/)
- [Cold Wallet](/glossary/cold-wallet/)
- [How Wallet Drainers Work](/guides/how-wallet-drainers-work/)