# Bitcoin Bips

> Bitcoin Improvement Proposals index, organized by topic.

Bitcoin Improvement Proposals index, organized by topic. Active soft
forks, wallet standards, network protocol, format standards. Pointers
to canonical text and historical context.
USE WHEN: looking up a BIP number, citing a standard, or understanding
the relationship between related BIPs.

- Page: https://ss33.ai/skills/claude-dev-suite/bitcoin-bips-99986511838
- Publisher: claude-dev-suite
- Category: [Finance & Markets](https://ss33.ai/skills/category/finance-and-markets-gri5ar) › [Payments & crypto](https://ss33.ai/skills/category/finance-and-markets-gri5ar/payments-and-crypto-jvjetm)
- License: MIT
- Source: https://github.com/claude-dev-suite/claude-dev-suite/blob/c32d3d81271b306861865a2397d594087cf0438b/skills/bitcoin/protocol/bips/SKILL.md

## Skill

SKILL.md: https://ss33.ai/api/v1/ss33/download/claude-dev-suite/bitcoin-bips-99986511838

# BIP Index (topic-organized)

Canonical: `https://github.com/bitcoin/bips`. As of September 2026 the
process is governed by BIP 3, and each BIP's status is exactly one of
four values:

- **Draft** — opened as a PR, still being worked on.
- **Complete** — authors concluded all planned work and recommend adoption.
- **Deployed** — a Complete BIP that has settled and is in active use.
- **Closed** — historical interest only; not worked on, promoted or in use.

The BIP 2 vocabulary (Proposed / Final / Active / Replaced / Withdrawn)
was retired in January 2026 and the repo no longer emits it. Header fields
are now `Layer` (Consensus (soft fork) | Consensus (hard fork) | Peer
Services | API/RPC | Applications), `Type` (Specification | Informational
| Process) and `Assigned` (the old `Created` field).

Publication is not endorsement: the repo states that a published BIP "is
in scope and has met other formal criteria for this repository, but does
not indicate that it is a good idea, has community consensus, or that it
is about to be adopted".

## Process

- **BIP 1, 2** — the original BIP process. BIP 2 is **Closed**, replaced
  by BIP 3.
- **BIP 3** — "Updated BIP Process" (Murch; assigned 2025-01-09, activated
  in the repo January 2026 via PR #1820, merged 2026-01-14; status
  **Deployed** as of September 2026). Streamlines BIP 2, reduces BIP
  Editor judgment calls, and defines the four-status model above.
- **BIP 123** — BIP layer classification (referenced by BIP 3).

## HD wallets and key derivation

- **BIP 32** — Hierarchical Deterministic Wallets.
- **BIP 39** — Mnemonic seed phrase.
- **BIP 43** — Purpose field convention.
- **BIP 44** — Multi-account hierarchy (legacy P2PKH).
- **BIP 49** — Derivation for P2SH-P2WPKH (`m/49'/0'/0'`).
- **BIP 84** — Derivation for native P2WPKH (`m/84'/0'/0'`).
- **BIP 86** — Derivation for P2TR (`m/86'/0'/0'`).
- **BIP 85** — Deterministic entropy from BIP32 (sub-seeds).

## Output and address formats

- **BIP 13** — P2SH addresses (`3...`).
- **BIP 16** — P2SH consensus rule.
- **BIP 141, 143, 144, 145, 147** — SegWit family.
- **BIP 173** — Bech32 (segwit v0).
- **BIP 350** — Bech32m (segwit v1+).
- **BIP 380–385** — Output descriptor language.
- **BIP 389** — Multipath descriptors.

## Taproot

- **BIP 340** — Schnorr signatures.
- **BIP 341** — Taproot output / key-path / script-path / merkle.
- **BIP 342** — Tapscript validation rules.

## PSBT

- **BIP 174** — PSBT v0.
- **BIP 370** — PSBT v2.
- **BIP 371** — Taproot fields in PSBT.

## Time locks and sequence

- **BIP 65** — `OP_CHECKLOCKTIMEVERIFY`.
- **BIP 68** — Relative locktime via nSequence.
- **BIP 112** — `OP_CHECKSEQUENCEVERIFY`.
- **BIP 113** — MTP for nLockTime.

## Mempool / replacement

- **BIP 125** — opt-in RBF.
- **BIP 152** — Compact block relay.
- **BIP 156** — "Dandelion - Privacy Enhancing Routing": stem/fluff
  relay that hides a transaction's origin. **Closed** as of September
  2026 and never implemented in Bitcoin Core — no Dandelion code at
  v31.1 (July 2026). Cite it as design history, not pending work.
- **BIP 157** — Compact block filter client.
- **BIP 158** — Compact block filter format.
- **BIP 331** — Ancestor package relay. Still **Draft** as of September
  2026; its wire messages (`sendpackages`, `ancpkginfo`, `pkgtxns`) are
  not in Bitcoin Core 31.1 (July 2026). What ships is mempool-side
  package evaluation: the `submitpackage` RPC and opportunistic 1p1c
  orphan resolution.
- **BIP 339** — wtxid relay.
- **BIP 431** — TRUC (v3) transactions.

## Network / P2P

- **BIP 31** — pong message.
- **BIP 35** — mempool message.
- **BIP 37** — Connection bloom filtering (deprecated).
- **BIP 130** — sendheaders.
- **BIP 155** — addrv2 (Tor v3, I2P, CJDNS).
- **BIP 324** — Version-2 P2P transport encryption.
- **BIP 330** — Erlay / transaction announcement reconciliation. Still
  **Draft** as of September 2026; no reconciliation round trip ships up
  to and including Bitcoin Core 31.1 (July 2026). Only the `sendtxrcncl`
  signaling half is merged (PR #23443, October 2022), behind the hidden
  debug-only `-txreconciliation` flag
  (`DEFAULT_TXRECONCILIATION_ENABLE{false}` in `src/net_processing.h` at
  v31.1). Full implementation PR #35591 (opened June 2026) is open and
  titled `[DO NOT MERGE]`; umbrella tracking issue #30249.

## Soft fork activation

- **BIP 8** — versionbits with lockinontimeout.
- **BIP 9** — versionbits.
- **BIP 34** — Block v2 (height in coinbase).
- **BIP 90** — Buried activation heights.

## Wallet UX standards

- **BIP 21** — URI scheme `bitcoin:address?amount=...&label=...`.
- **BIP 47** — Reusable Payment Codes (PayNyms).
- **BIP 78** — PayJoin.
- **BIP 137** — Generic message signing.
- **BIP 322** — Generic signed message format (modern).
- **BIP 329** — Wallet labels portability.
- **BIP 352** — Silent Payments.

## Multi-party signatures

- **BIP 327** — MuSig2 (Schnorr key aggregation).

## Hardware wallets

- **BIP 174 / 370 / 371** — PSBT (also covers HW signing).
- **BIP 388** — Wallet policies for HWs (Ledger, etc.).

## Proposals (not active on mainnet)

Statuses below are as carried by the BIPs `README.mediawiki` index in
September 2026.

- **BIP 53** — "Disallow 64-byte transactions" (Chris Stewart). **Draft**.
- **BIP 54** — "Consensus Cleanup" (Poinsot, Corallo). **Complete** —
  i.e. the authors recommend adoption; it is not activated on mainnet.
- **BIP 110** — "Reduced Data Temporary Softfork" (Dathon Ohm, assigned
  2025-12-03). Consensus caps on arbitrary data, deployed on bit 4 with a
  55% threshold and a mandatory-signaling window starting at block
  961,632 (2026-08-08). Signaling stayed far below threshold, enforcing
  nodes split onto a chain that stalled, and the BIPs repo moved it to
  **Closed** on 2026-08-10. Cite it as a failed activation, not a rule.
- **BIP 118** — `SIGHASH_ANYPREVOUT` / `ANYPREVOUTANYSCRIPT`. **Draft**.
- **BIP 119** — `OP_CHECKTEMPLATEVERIFY` (CTV). **Draft**.
- **BIP 300/301** — Hashrate Escrows / Blind Merged Mining
  (Drivechains). Both **Draft**.
- **BIP 345** — `OP_VAULT`, `OP_VAULT_RECOVER`. **Closed**, and its
  header carries `Proposed-Replacement: 443`. Cite it as design history,
  not as a live proposal; BIP 443 (`OP_CHECKCONTRACTVERIFY`) is the
  successor.
- **BIP 347** — `OP_CAT` in Tapscript (Heilman, Sabouri). **Complete**,
  likewise not activated.
- **BIP 360** — Pay-to-Merkle-Root (P2MR), a post-quantum output type
  (Beast, Heilman, Foxen Duke). **Draft**.
- **BIP 361** — "Post Quantum Migration and Legacy Signature Sunset"
  (Lopp et al.), Informational. **Draft**.

The 2026 script / covenant cluster, all **Draft** as of September 2026
and none deployed:

- **BIP 440** — Varops Budget For Script Runtime Constraint (Russell, Moik).
- **BIP 441** — Restoration of disabled script, Tapleaf 0xC2 (Russell, Moik).
- **BIP 442** — `OP_PAIRCOMMIT` (moonsettler, Brandon Black).
- **BIP 443** — `OP_CHECKCONTRACTVERIFY` (Salvatore Ingala); the
  proposed replacement for BIP 345.
- **BIP 446** — `OP_TEMPLATEHASH` (Sanders, Poinsot, Roose).
- **BIP 448** — Taproot-native (Re)bindable Transactions (Sanders,
  Poinsot, Roose).
- **BIP 449** — `OP_TWEAKADD`, x-only key tweak addition (Jeremy Rubin).

## Reading order for newcomers

1. BIP 32 → 39 → 84 → 174 (foundations of any wallet).
2. BIP 141/143/144 (SegWit).
3. BIP 340/341/342 (Taproot).
4. BIP 380–385 (descriptors).
5. BIP 327 (MuSig2) and BIP 322 (message signing).

## Lookups

- Repo: `github.com/bitcoin/bips`.
- Master index file: `README.mediawiki` lists all BIPs with status.
- Some BIPs are **Closed** (withdrawn, replaced or abandoned); check the
  status field before citing. Under BIP 3 a Closed BIP carries no
  implication that it was ever deployed — see BIP 110 above.

## See also

- [consensus/SKILL.md](../consensus/SKILL.md)
- [proposals/SKILL.md](../proposals/SKILL.md)
- [psbt/SKILL.md](../psbt/SKILL.md)
- [descriptors/SKILL.md](../descriptors/SKILL.md)