BA-14 · LESSON 07

BIP design and review

KEY DEFINITIONS

Terms used in this lesson

BIP: Bitcoin Improvement Proposal: a numbered technical document describing a Bitcoin standard, process, or proposed change.
Tapscript: The version of Bitcoin Script used by a Taproot script-path spend.
OP_SUCCESS: A family of Tapscript opcode bytes that make old nodes immediately accept the script, leaving room for a future soft-fork restriction.
OP_VERIF: A disabled Bitcoin Script opcode whose execution is invalid under existing consensus rules.

Protocol proposals need precise motivation, compatibility, activation, test vectors, security analysis, and reference behavior.

55 min Difficulty 4/5 Not started

VISUAL MODEL

See the whole mechanism before going step by step

Use the diagrams to orient yourself. Then the guided explanation below teaches every part in depth.

4 explanatory views

CONCEPT-SPECIFIC MAP · state machineOne valid action transforms a known stateSelect any state to inspect its exact role.

RELATIONSHIP MAPOrdered mechanism flow

01
BEFOREKnown state
Identify the facts and objects that exist before the action.
02
ACTIONBIP design and review
The BIP design and review lesson isolates the event that proposes a change.
03
RULEDeterministic check
The enforcing rule accepts or rejects the proposed transition.
04
AFTERSuccessor state
Accepted work creates a new state without silently changing the prior facts.
05
FAILUREState unchanged
A failed condition must not produce a partially accepted successor.

Rule shown: A valid transition names the prior state, action, enforcing rule, and successor state.

STAGE 1 OF 5BEFORE: Known state

Identify the facts and objects that exist before the action.

Governing relationship: A valid transition names the prior state, action, enforcing rule, and successor state. Complete path: 1. BEFORE, Known state. Identify the facts and objects that exist before the action. 2. ACTION, BIP design and review. The BIP design and review lesson isolates the event that proposes a change. 3. RULE, Deterministic check. The enforcing rule accepts or rejects the proposed transition. 4. AFTER, Successor state. Accepted work creates a new state without silently changing the prior facts. 5. FAILURE, State unchanged. A failed condition must not produce a partially accepted successor.

1. State transitionWhat exists, what changes, and what results

BEFORE

Compare Tapscript OP_SUCCESS byte 0xc1 with old-invalid OP_VERIF byte 0x65.

MECHANISM

Show a concrete unmet need, existing alternatives, affected users, and why a consensus or interoperability change is justified.

AFTER

Compatibility follows the old and new consensus-valid sets, not an opcode label or proposal intent.

Text equivalent: Starting from Compare Tapscript OP_SUCCESS byte 0xc1 with old-invalid OP_VERIF byte 0x65. The mechanism begins when Show a concrete unmet need, existing alternatives, affected users, and why a consensus or interoperability change is justified. The resulting lesson is Compatibility follows the old and new consensus-valid sets, not an opcode label or proposal intent.

2. Mechanism pathSelect a stage to inspect its job

STAGE 1 OF 5

Define the problem and scope

Show a concrete unmet need, existing alternatives, affected users, and why a consensus or interoperability change is justified.

Complete path: 1. Define the problem and scope: Show a concrete unmet need, existing alternatives, affected users, and why a consensus or interoperability change is justified. 2. Specify exact behavior: Define bytes, state transitions, validation, error cases, resource limits, versioning, and normative terms so independent implementers agree. 3. Analyze compatibility: Classify soft-fork, hard-fork, policy, wallet, or application effects and describe old-software behavior. 4. Provide executable evidence: Canonical valid and invalid vectors, reference logic, fuzz targets, and deployment simulations expose ambiguity. 5. Plan activation and rollback limits: State readiness signals, lock-in, activation, failure handling, monitoring, and which consensus changes cannot simply be rolled back after funds depend on them.

3. Rule and failure boundaryWhat accepts the result and where it can stop

ACCEPTED PATH

Bounded old and upgraded interpreters execute every learner vector at pre-activation and post-activation heights, apply resource limits, and derive compatibility from the resulting validity sets.

CHANGED CONDITION

Arbitrary prose or bytes, ambiguous rules, vector expectation mismatches, unsafe activation, excess resource use, or validity expansion mislabeled as a soft fork rejects the package.

Important distinction: A compelling use case is enough detail for a consensus BIP. Motivation explains why. Consensus safety requires deterministic specification, compatibility, vectors, adversarial analysis, and deployment.

Text equivalent: The accepted path is enforced by Bounded old and upgraded interpreters execute every learner vector at pre-activation and post-activation heights, apply resource limits, and derive compatibility from the resulting validity sets. If the required condition changes, Arbitrary prose or bytes, ambiguous rules, vector expectation mismatches, unsafe activation, excess resource use, or validity expansion mislabeled as a soft fork rejects the package.

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Learn the idea

A BIP design document makes a Bitcoin change reviewable. It states motivation, specification, rationale, backwards compatibility, reference or test vectors, security analysis, and deployment considerations. Consensus proposals need byte-exact behavior and activation rules, while informational or application standards may not change consensus.

GUIDED EXPLANATION1/5 ideas inspected

Define the problem and scope

Show a concrete unmet need, existing alternatives, affected users, and why a consensus or interoperability change is justified.

The worked example follows the explanation

Inspect every idea above to open it.

Important distinction“A compelling use case is enough detail for a consensus BIP.”

Motivation explains why. Consensus safety requires deterministic specification, compatibility, vectors, adversarial analysis, and deployment.

FINISH LEARNING FIRST

The questions unlock after every required learning activity

Inspect every guided idea, open the worked example, rebuild its mechanism, and complete the deterministic lesson tool. Your progress is saved automatically.