UST Protocol — the Bitcoin/OTS anchor verifier

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Browser: node-only. This package does not run in a browser, and that is a decision rather than an omission. See ust:browser.why in its package.json for the reason, and UST-Protocol#148 for what a browser can and cannot reach without it. A page is not left without a route: the core delegates the substrate through the consumer-supplied substrateVerify faculty by design, so a browser reaching for an anchored verdict supplies its own — which is a connector you replace, not a capability the core lacks. What a browser cannot do is install THIS one and have it work.

UST (Universal State Transcript) is trust infrastructure for data: a signed, canonical, tamper-evident record of state — some data about the world at a moment — that verifies the same however it reached you. TLS secures the pipe; UST secures the payload, so the guarantee travels with the data instead of with the connection.

Two rules this protocol does not trade away. A minor only ADDS. Anything that changes the meaning of what an earlier minor already defines is a MAJOR — there is no third option, because an older verifier evaluating under older rules must still be RIGHT about what it evaluated. A verifier never expires. An older verifier keeps producing correct verdicts about everything it understands; newer material it does not implement is reported as NOT EVALUATED — never as invalid, never silently passed. Whether that reach is enough is the CONSUMER's policy, not the protocol's coercion. Both hold today: a newer minor answers INDETERMINATE(unsupported_minor) and a different major INDETERMINATE(unsupported_major) — never INVALID, which means only "I applied MY rules and they were violated".

The opt-in Bitcoin cross-check for UST anchors. The zero-dependency reference verifier (ust-protocol) never embeds a blockchain — a portable verifier must not carry a Bitcoin node. It takes substrateVerify as an injection; this package is that injection, backed by OpenTimestamps.

Install

npm i @ust-protocol/ots-verify

import { substrateVerify } from '@ust-protocol/ots-verify';
import { resolveByDiscovery } from 'ust-protocol';

const { verdict } = await resolveByDiscovery(doc, { context: 'data' }, { substrateVerify });
// witness genesis anchor cross-checked against Bitcoin → VALID:HIGH when the anchor is final

Without it, an anchor is honestly unproven → the verdict reports HIGH pending (never a faked HIGH). With it, the witness genesis's Bitcoin-OTS anchor is verified: { final, time }.

The ust CLI and @ust-protocol/mcp auto-detect this package (a graceful dynamic import) — install it to turn on the cross-check; nobody is forced to.