490 / 691FP

Wallet Fingerprint

Short fingerprint of the wallet’s master key

Wallet Fingerprint usually means a short fingerprint of the BIP32 master public key. It helps distinguish keys and check recovery, but possible collisions mean it cannot establish the identity of the whole wallet on its own.

A BIP32 fingerprint consists of the first 4 bytes of HASH160 of the compressed public key: SHA-256 followed by RIPEMD-160. It is 32 bits, usually written as 8 hexadecimal characters. The chain code is not included.

The calculation uses the serialized public key, not seed words or the private key as a direct input. The short fingerprint is an auxiliary identifier; it is not a receiving address, cannot sign a transaction and does not contain the data needed to recover the wallet. [BIP32 — Key identifiers and serialization]

An xpub or xprv record contains the fingerprint of that key’s parent. For a master key, this field is 00000000 because it has no parent; it is not the master key’s own fingerprint. An application may display the master key’s own fingerprint, so check the field’s meaning and derivation level when comparing. [BIP32 — Key identifiers and serialization]

For the master key in BIP32 public test vector 1, its own fingerprint is 3442193e. The parent field in its master xpub remains 00000000. This is a public test example, not a safe foundation for a wallet holding your funds. [BIP32 — Key identifiers and serialization]

Under BIP174, a PSBT associates the master fingerprint with the derivation path for the relevant public key. An Output Descriptor can also specify the origin fingerprint and path. Recognizing change requires more than a matching fingerprint: the signer must derive and compare the actual key and corresponding script conditions. [BIP174 — Key origins and change detection] [BIP380 — Output Script Descriptors]

With 32 bits there are only 4294967296 possible values, so different keys can have the same fingerprint. BIP32 requires software to handle collisions. A match does not verify the complete set of accounts, derivation paths, script types or availability of private keys. [BIP32 — Key identifiers and serialization] [BIP380 — Output Script Descriptors]

Compare the same kind of fingerprint at the same derivation level. A difference may indicate a different seed or passphrase, but first rule out confusion between master and parent fields. Supplement a match by checking known addresses and the correct paths and scripts; the fingerprint alone cannot replace a securely stored backup or a verified recovery procedure. [BIP32 — Key identifiers and serialization] [BIP380 — Output Script Descriptors]

For the clearest picture, read this entry together with HD Wallet, PSBT, BIP39 passphrase, Output Descriptor.

DOC · 001BIP32 — Key identifiers and serializationSpecification ↗DOC · 002BIP174 — Key origins and change detectionSpecification ↗DOC · 003BIP380 — Output Script DescriptorsSpecification ↗
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