Derivation scheme for P2WPKH-nested-in-P2SH based accounts

The five-minute read

One action, walked through

1. Open BIP 49 and read the status line before the examples.
2. Write down the rule in one sentence. A fair version of that sentence is: The derivation scheme for HD wallets using the P2WPKH-nested-in-P2SH ([[bip-0141.mediawiki|BIP 141]]) serialization format for segregated witness transactions.
3. Name the object that changes: P2WPKH, P2SH.
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 49 at the status the text itself states: Deployed.
• The object that has to change is P2WPKH, P2SH. A neighbouring document with a similar name is not this one.
• Status in the header is not adoption.

What happened after the paper

The source marks this deployed. That is a statement about the text, not a promise that every wallet or node has shipped it. Later documents can narrow, replace, or ignore this one. Cite the number you mean.

What to check before you use the idea

• What must an implementation of Derivation scheme for P2WPKH-nested-in-P2SH based accounts accept, and what may it ignore?
• Is this consensus, peer policy, or an application interface?
• Which names does the text pin down: P2WPKH, P2SH?

Terms

BIP 49

The public text titled Derivation scheme for P2WPKH-nested-in-P2SH based accounts.

Deployed

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

The problem the paper names

An interface that is only a name in a repository will be re-implemented differently by every team, which is how shared contracts break.

What the design proposes

• The derivation scheme for HD wallets using the P2WPKH-nested-in-P2SH ([[bip-0141.mediawiki|BIP 141]]) serialization format for segregated witness transactions.
• With the usage of P2WPKH-nested-in-P2SH ([[bip-0141.mediawiki#p2wpkh-nested-in-bip16-p2sh|BIP 141]]) transactions it is necessary to have a common derivation scheme.
• It allows the user to use different HD wallets with the same masterseed and/or a single account seamlessly.

How the mechanism is specified

• Taken from the specification, the next constraint is: With the usage of P2WPKH-nested-in-P2SH ([[bip-0141.mediawiki#p2wpkh-nested-in-bip16-p2sh|BIP 141]]) transactions it is necessary to have a common derivation scheme.
• Locate P2WPKH, P2SH in BIP 49 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

• This document does not set a fee, a valuation, or a security proof.
• Status in the header is not adoption.
• The source marks this deployed. That is a statement about the text, not a promise that every wallet or node has shipped it.

Why a venture studio still reads it

Use BIP 49 when a pitch says 'Derivation scheme for P2WPKH-nested-in-P2SH based accounts' without saying whether the rule is consensus, policy, or an interface. The number is the citation. The pitch is not.