7 standards
Something that changes over time has to be recorded somewhere. Standards here keep a value in an output's own locking script and carry it forward on each spend, instead of paying for a long chain of transactions to record every event.
Also searched as state machine, event chain, covenant state, counter, state.
7 standards, spread across 4 of the 12 topics.
A Bitcoin contract that needs to change some stored value on every spend has only one trustworthy place to keep that value: inside its own locking script. But Bitcoin Script can only cut a script apart at fixed byte positions, so two developers solving this independently end up with two incompatible layouts, and neither their tools nor anyone else's contracts can read the other's state. This describes a shared, self-describing way to lay out that state so any script, wallet, or third-party contract can find and read it without being told anything else about it.
Filed under State machines
On-chain state is the main subject of these 3.
Applications constantly need somewhere to keep small pieces of state, and doing that on chain usually means inventing a scheme per project. This standardises a simple named-value store: a public one others can discover, and a private one held in the wallet.
Recording a long series of events on chain by chaining one transaction to the next gets expensive and slow. This describes carrying the same history as a chain of hashes inside a single transaction that keeps being updated instead.
A Bitcoin contract that needs to change some stored value on every spend has only one trustworthy place to keep that value: inside its own locking script. But Bitcoin Script can only cut a script apart at fixed byte positions, so two developers solving this independently end up with two incompatible layouts, and neither their tools nor anyone else's contracts can read the other's state. This describes a shared, self-describing way to lay out that state so any script, wallet, or third-party contract can find and read it without being told anything else about it.
These are about something else, and deal with on-chain state on the way.
Letting a computer program spend Bitcoin on its own usually means handing it a private key, and a key can sign for anything, not just the one task it was meant for. Even a lightly funded key is a full custodian, which is risky when the program is something like an AI agent reading untrusted instructions. This describes a way to let a program trigger on-chain steps and pay their fees automatically, without ever holding a key that could send money elsewhere.
A digital collectible is normally just a picture plus a boring list of past owners nobody looks at. This standard describes a way for the picture itself to change over time and with use, so that a piece can visibly age, shift with the seasons, or wear a mark its owner chose, all computed fresh by anyone looking rather than fetched from a server.
Signing a contract online today means trusting one company's database to say who signed, in what order, and when. If that company shuts down, gets bought, or gets compelled by a court, the "proof" you have is just whatever it says it is. This makes it possible for the proof of a signing to survive and be checked by anyone, long after the company that ran the signing is gone.
Concepts that keep appearing on the same standards as this one.
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