DOCS / RECEIPTS

Answers that can't be quietly edited.

APIs get cached, proxied, re-served and screenshotted. Somewhere along that chain, numbers get edited — sometimes by accident, sometimes not. A FlipForge receipt makes that tampering detectable by anyone, forever: the signature binds the exact query, the exact result, the slot it was observed at and the moment it was issued.

Verification is deliberately boring. Rebuild the canonical JSON (keys sorted, deterministic bytes), hash it with SHA-256, check that hash against answerDigest, then check the ed25519 signature against the published key. No network calls. No account. It works in an airgapped room.

Anatomy

"receipt": {
  "query":        "mint:2b1kV6Dk…u24GXo@mainnet",
  "answerDigest": "9f47be94…",   // sha-256 of the canonical answer
  "slot":         432889174,      // observed slot
  "issuedAt":     1784044509838,  // unix ms
  "sig":          "1e9cf0d1…"    // ed25519 over the digest
}▌

Verifying without the SDK

The whole recipe is ~30 lines with noble. If you use flipforge-sdk, this is ff.verify(signed).

import { verifyAsync, hashes, etc } from "@noble/ed25519";
import { sha512, sha256 } from "@noble/hashes/sha2.js";
hashes.sha512Async = async (...m) => sha512(etc.concatBytes(...m));

const PUBKEY = "59bd5714f8c76aeb45f27f55eb0d4aec3e0f9d761205a67d96d59f6b65a36b8f";

function canonical(v) {
  if (Array.isArray(v)) return v.map(canonical);
  if (v && typeof v === "object")
    return Object.fromEntries(Object.keys(v).sort().map(k => [k, canonical(v[k])]));
  return v;
}

async function verify(signed) {
  const { result, receipt } = signed;
  const bytes = new TextEncoder().encode(JSON.stringify(canonical({
    query: receipt.query, result, slot: receipt.slot, issuedAt: receipt.issuedAt,
  })));
  const digest = sha256(bytes);
  const hex = [...digest].map(b => b.toString(16).padStart(2, "0")).join("");
  if (hex !== receipt.answerDigest) return false;
  return verifyAsync(receipt.sig, digest, PUBKEY);
}▌