Pay to Anchor (P2A)

The five-minute read

One action, walked through

1. Open BIP 433 and read the status line before the examples.
2. Write down the rule in one sentence. A fair version of that sentence is: This document describes a new standard output script called Pay to Anchor (P2A) and prescribes making spending of this output type standard.
3. Name the object that changes: P2A, CPFP, TRUC.
4. Ask what an old client, an old contract, or an offline counterparty does. If the document is silent, the silence is part of the design.

The argument, unpacked

What has to be true

• You are implementing BIP 433 at the status the text itself states: Draft.
• The object that has to change is P2A, CPFP, TRUC. A neighbouring document with a similar name is not this one.
• Constants in the text can be superseded by a later fork. Cite the EIP number and the fork you mean.

What happened after the paper

The source marks this draft. It is not a live consensus rule just because it has a number. Later documents can narrow, replace, or ignore this one. Cite the number you mean.

What to check before you use the idea

• What does Pay to Anchor (P2A) charge, reject, or redefine on the first touch versus a later one?
• Does a reverted subcall roll the change back?
• Can you point at the object in a client: P2A, CPFP, TRUC?

Terms

BIP 433

The public text titled Pay to Anchor (P2A).

Draft

The document's own label for how finished the text is. It is not a market fact.

The problem the paper names

An underpriced or ambiguous EVM rule is not a feature. It is a block that takes longer than the gas limit claimed, or a client that disagrees about the result.

What the design proposes

• This document describes a new standard output script called Pay to Anchor (P2A) and prescribes making spending of this output type standard.
• This output is "keyless" meaning no signature or witness data at all are required to spend this output type.
• The "anchor" output type is a commonly used pattern in Bitcoin layer 2 systems such as Lightning Network and beyond.

How the mechanism is specified

• Taken from the specification, the next constraint is: This output is "keyless" meaning no signature or witness data at all are required to spend this output type.
• Locate P2A, CPFP, TRUC in BIP 433 and apply it to one transaction or call.
• Then check the failure the class of rule always has: a node that did not upgrade, a reverted call, a replayed signature, or a peer that does not speak the message.

What this page does not treat as proven

• A gas or opcode change is not a throughput benchmark. It is a relative price and a validity rule.
• Constants in the text can be superseded by a later fork. Cite the EIP number and the fork you mean.
• The source marks this draft. It is not a live consensus rule just because it has a number.

Why a venture studio still reads it

Use BIP 433 when a pitch says 'Pay to Anchor (P2A)' without saying whether the rule is consensus, policy, or an interface. The number is the citation. The pitch is not.