TERM_DEF // UPGRADES_BIPS / BIP_43_HD_WALLET_PURPOSE_FIELD
BIP 43 (HD
WALLET PURPOSE FIELD)
WALLET PURPOSE FIELD)
BIP 43 (wallet-hierarchical-deterministic/">HD Wallet Purpose Field). Introduced the purpose' field for derivation paths.
This page sits in the Upgrades & BIPs section — The proposal process and the major upgrades that shaped Bitcoin. Read on for what it is, why it exists, how it works under the hood, and what to watch out for.
This page sits in the Upgrades & BIPs section — The proposal process and the major upgrades that shaped Bitcoin. Read on for what it is, why it exists, how it works under the hood, and what to watch out for.
WHAT_BIP_43_HD_WALLET_PURPOSE_FIELD_IS
BIP 43 (HD Wallet Purpose Field) — at a glance
UPGRADES
BIP 43 — "HD Wallet Purpose Field" is a proposal in the HD Wallets family, first published in 2014 with status active. Introduced the purpose' field for derivation paths. Its technical mechanism: reserves m/<purpose'>/... so different wallet schemes can coexist. foundation for BIPs 44/49/84/86
Why it exists
DESIGN
BIP 43 (HD Wallet Purpose Field) exists to solve a specific problem: give HD-wallet derivation paths a purpose-level namespace. Without a written, numbered spec, every wallet and node implementer would interpret the requirement differently — and Bitcoin's value depends on every implementation agreeing exactly. BIP-43 is the single source of truth for this concern, so any new client built today can match the behaviour of every client built since 2014.
HOW_IT_WORKS
Mechanism
HOW IT WORKS
Mechanically, BIP-43 reserves m/<purpose'>/... so different wallet schemes can coexist. Adoption today: foundation for BIPs 44/49/84/86.
1. Author drafts BIP-43 against the BIP-2 template — abstract, motivation, specification, rationale.
2. The text + a reference implementation are posted on the bitcoin-dev list and as a PR to bitcoin/bips.
3. Reviewers tear it apart: ambiguities, security concerns, edge cases, interaction with prior BIPs.
4. Once stable, the BIP editor merges it; it gets a number (BIP-43) and the status "draft" or "proposed".
5. Implementations land in Bitcoin Core / wallets / other clients. For consensus changes: activation parameters chosen.
6. After deployment + adoption, BIP-43 is promoted to "final"; deprecated proposals get "replaced" or "withdrawn".
WORKED_EXAMPLE
BIP-43 — quick reference card
EXAMPLE
BIP number : 43
Title : HD Wallet Purpose Field
Area : HD Wallets
First published: 2014
Status : active
Fork class : no
Motivation : give HD-wallet derivation paths a purpose-level namespace.
Mechanism : reserves m//... so different wallet schemes can coexist.
Where it shows up : foundation for BIPs 44/49/84/86.
Read the spec : https://github.com/bitcoin/bips/blob/master/bip-0043.mediawiki
KEY_PROPERTIES
OPT-IN
No authority can force a BIP on anyone. Adoption depends entirely on whether the change is genuinely useful.
NUMBERED
Stable numeric reference — BIP-43 means the same thing across every wallet, miner, and node that has read this spec.
NON-CONSENSUS
BIP-43 is not a consensus rule — clients can implement it without coordinating with the network at large.
DEPLOYED
Implementations of BIP-43 are in production. The behaviour is observable on mainnet today.
COMMON_PITFALLS
Things that catch people out
PITFALLS
- Don't confuse "draft" / "proposed" / "final" status — read the BIP header before relying on it in production.
- The BIP number is just an editorial counter — it doesn't imply correctness or stability. Always cross-reference with the latest bitcoin/bips repo.
RELATED_CONCEPTS
Other terms from Upgrades & BIPs — click any to read its page:
TERMINOLOGY_INDEX
TERMINOLOGY
BIP 43 (HD Wallet Purpose Field)
Introduced the purpose' field for derivation paths.
Segregated Witness (SegWit, BIP 141)
The 2017 upgrade separating witness-data/">witness data, fixing tx malleability, and introducing weight units.
Taproot (BIP 341)
Tapscript (BIP 342)
Script-language updates accompanying Taproot — new opcodes, removed limits.
Schnorr (BIP 340)
The Schnorr signature spec adopted by Taproot.
BIP Process
The community workflow for proposing, discussing, and tracking changes to Bitcoin.
Soft Fork Activation
MASF (Miner-Activated Soft Fork)
Activation triggered by miner signaling in block versions.