Ask/Knowledge Atlas/BIP39 passphrase
Wallets & custody · Maintained 2026

BIP39 passphrase

A BIP39 passphrase is optional input combined with mnemonic words during seed derivation; every passphrase produces a valid-looking but different seed, so loss or error can make the intended wallet unrecoverable.

Context

Why it matters

A BIP39 passphrase is optional input combined with mnemonic words during seed derivation; every passphrase produces a valid-looking but different seed, so loss or error can make the intended wallet unrecoverable.

Canonical knowledge

What California Bitcoin maintains

  • A BIP39 passphrase is optional input combined with mnemonic words during seed derivation; every passphrase produces a valid-looking but different seed, so loss or error can make the intended wallet unrecoverable.

Primary and technical sources

Evidence before assertion
BIP39: Mnemonic code for generating deterministic keys

Bitcoin BIPs

Tier 1 · primary

Related concepts

Continue through the knowledge graph
Seed phrasesHD walletsSelf-custody
Machine accessAgent-ready
https://californiabitcoin.org/api/agent/v1/topic/bip39-passphrasehttps://californiabitcoin.org/api/agent/v1/search?q=BIP39%20passphrasehttps://californiabitcoin.org/api/agent/v1/coveragehttps://californiabitcoin.org/api/agent/v1/sources