Non-Fungible Key Bound Token

The five-minute read

One action, walked through

1. Open ERC 6809 and read the status line before the examples.
2. Write down the rule in one sentence. A fair version of that sentence is: A standard interface for Non-Fungible Key Bound Tokens (NFKBT/s), a subset of the more general Key Bound Tokens (KBT/s).
3. Name the object that changes: NFKBT, KBT, API.
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 ERC 6809 at the status the text itself states: Final.
• The object that has to change is NFKBT, KBT, API. A neighbouring document with a similar name is not this one.
• Wallet support is not the same as consensus validity.

What happened after the paper

The source marks this final. 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 is covered by the signed bytes in Non-Fungible Key Bound Token?
• Can the same signature be replayed on another chain, account, or message?
• Which primitive does the text require: NFKBT, KBT, API?

Terms

ERC 6809

The public text titled Non-Fungible Key Bound Token.

Final

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

The problem the paper names

A signature that does not commit to what the user saw can be replayed into a different spend, a different chain, or a different message.

What the design proposes

• A standard interface for Non-Fungible Key Bound Tokens (NFKBT/s), a subset of the more general Key Bound Tokens (KBT/s).
• The following standardizes an API for tokens within smart contracts and provides basic functionality to the addBindings function.
• This function designates Key Wallets[^1], which are responsible for conducting a Safe Transfer[^2].

How the mechanism is specified

• Taken from the specification, the next constraint is: The following standardizes an API for tokens within smart contracts and provides basic functionality to the addBindings function.
• Locate NFKBT, KBT, API in ERC 6809 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 signature scheme is not a privacy system. It hides the signer only if the protocol says so.
• Wallet support is not the same as consensus validity.
• The source marks this final. 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 ERC 6809 when a pitch says 'Non-Fungible Key Bound Token' without saying whether the rule is consensus, policy, or an interface. The number is the citation. The pitch is not.