Passphrase generation

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Bump passphrase strength requirements ← Older revision Revision as of 06:49, 31 July 2026 Line 22: Line 22: * The passphrase on a wallet file that has become public, or that an attacker has otherwise gained access to. * The passphrase on a wallet file that has become public, or that an attacker has otherwise gained access to. * The input to a "brain wallet". ('''Warning:''' it is very strongly recommended that you not attempt to use a brain wallet.) * The input to a "brain wallet". ('''Warning:''' it is very strongly recommended that you not attempt to use a brain wallet.) * Any wallet encrypted with a dictionary password or any other easy-to-guess password. Example of keys that could be cracked by a targeted search: Example of keys that could be cracked by a targeted search: Line 27: Line 28: * The passphrase on a wallet file that may become public, or that an attacker could gain access to. * The passphrase on a wallet file that may become public, or that an attacker could gain access to. * The input to a secure "brain wallet" with e-mail salting, and an expensive Key Derivation Function. * The input to a secure "brain wallet" with e-mail salting, and an expensive Key Derivation Function. * Seed phrases stored in your e-mail. === Standards for offline passphrases === === Standards for offline passphrases === Between 64 and 80 bits of entropy seems reasonable. The password must be totally random (see later sections on generation). Hardware wallets have additional protections, and it's OK that they often allow only a short PIN. Between 64 and 80 bits of entropy seems reasonable. The password must be totally random (see later sections on generation). Hardware wallets have additional protections, and it's OK that they often allow only a short PIN . However it is preferrable to use more entropy . This corresponds to the following password/passphrase lengths: This corresponds to the following password/passphrase lengths: Line 46: Line 48: === Standards for online passphrases === === Standards for online passphrases === Usually you don't have to personally generate an online passphrase. The most common case of an online passphrase in Bitcoin is the mnemonic for an HD wallet seed, but a good wallet should securely generate it for you (this is the several-word mnemonic that most wallets tell you to write down when first run), assuming it has not been tampered with. The most common case of an online passphrase in Bitcoin is the mnemonic for an HD wallet seed, but a good wallet should securely generate it for you (this is the several-word mnemonic that most wallets tell you to write down when first run), assuming it has not been tampered with. In case you need to manually generate an online passphrase, 128 bits of entropy is required. The passphrase must be totally random (see later sections on generation). In case you need to manually generate an online passphrase, 128 bits of entropy is required. The passphrase must be totally random (see later sections on generation) . Nowadays with more powerful GPU clusters available, it is mandatory to use this kind of strong passphrase . This corresponds to the following password/passphrase lengths: This corresponds to the following password/passphrase lengths: