Attestations

const commitment = await sha256Hex(`${secret}|${saltHex}|${interactionId}|${me.appUserId}`);
const receipt = await zend.attest({ label: "commit", dataHash: commitment, interactionId });

// ...play...

await zend.attest({
  label: "reveal",
  dataHash: await sha256Hex(`${secret}|${saltHex}`),
  interactionId,
});

{
  id: number;
  app: string;
  app_user_id: string;
  interaction_id: string;
  label: string;
  data_hash: string;
  prev_hash: string;   // links to the previous receipt
  unix_ms: number;
  receipt_hash: string;
  signature: string;   // Ed25519 by Zend
}

curl https://api.usezend.app/api/zend/v2/apps/attest/interactions/int_...
curl https://api.usezend.app/api/zend/v2/apps/attest/key

import { verifyAttestation } from "@zendfi/appkit/server";

// { "alg": "ed25519", "public_key": "<hex>" }
const { public_key } = await (await fetch("https://api.usezend.app/api/zend/v2/apps/attest/key")).json();
const ok = verifyAttestation(receipt, public_key);