Sybil Attack

<script type="module">
  const mod = await import(
    'https://cdn.shieldlabs.ai/snippet.js?publicKey=YOUR_PUBLIC_KEY'
  );
  // A fresh identification for the claim, started when the page opens so it
  // is sent while the user reads it. onInitialized fires when the check starts,
  // before the snippet sends it, so it only stores the request ID and the form
  // submits normally. With no request ID, your backend routes the claim to
  // verification. Pass a hash of the connected wallet address, never the raw address.
  mod.forceCheckAuthenticatedUser(hashWallet(walletAddress), {
    onInitialized: (result) => {
      if (result.status === 'initialized') {
        document.getElementById('shieldlabs-request-id').value = result.requestID;
      }
    },
  });
</script>

<form id="claim-form" method="POST" action="/api/claim">
  <input type="hidden" id="shieldlabs-request-id" name="shieldlabsRequestId" />
  <button type="submit">Claim</button>
</form>

curl "https://account.shieldlabs.ai/api/v1/history/device_id/5eb7fd5c-2a1b-4c3d-9e8f-7a6b5c4d3e2f?limit=100" \
  -H "Authorization: Bearer sec_your_private_api_key"

import { app, waitForScore, band, accountView, accountsBehindDevice, NIL_DEVICE } from '../shieldlabs-helpers.js';

app.post('/api/claim', async (req, res) => {
  const { walletAddress, shieldlabsRequestId } = req.body;
  const userHid = hashWallet(walletAddress); // the same hash the browser passed

  // 1. Your normal eligibility checks first (wallet eligible, not already
  //    paid, within the claim window).
  if (!(await walletIsEligible(walletAddress))) {
    return res.status(409).json({ error: 'wallet_not_eligible' });
  }

  // 2. The guard: read this claim's identification. It must belong to this
  //    wallet. No identification is unverified, never clean.
  const risk = await waitForScore(shieldlabsRequestId, 2000);
  if (!risk) return res.json({ status: 'verify', reason: 'no_identification' });
  if (risk.user_hid !== userHid) {
    return res.json({ status: 'verify', reason: 'identification_mismatch' });
  }
  if (risk.risk_score > 100) {
    return res.json({ status: 'verify', reason: 'rate_limit_marker' }); // the 999 marker
  }

  // 3. The wallet: your Multi-accounting mark ('medium' or 'high', your own
  //    store), then its earlier identifications without this one.
  const marked = await markedWallets.get(userHid);
  if (marked === 'high') return res.json({ status: 'review', reason: 'held_for_review' });
  // A failed History read is unverified: route the claim to verification.
  const wallet = await accountView(userHid, { excludeRequestId: risk.request_id }).catch(() => null);
  if (!wallet) return res.json({ status: 'verify', reason: 'history_unavailable' });
  if (marked || wallet.worstBand === 'Dangerous') {
    return res.json({ status: 'verify', reason: 'risky_wallet' });
  }

  // 4. An all-zero Device ID means no usable device signals reached ShieldLabs:
  //    there is no device to count wallets on, so route the claim to verification.
  if (risk.device_id === NIL_DEVICE) {
    return res.json({ status: 'verify', reason: 'no_device' });
  }

  // 5. Distinct wallets behind this device.
  const walletsOnDevice = await accountsBehindDevice(risk.device_id).catch(() => null);
  if (walletsOnDevice === null) return res.json({ status: 'verify', reason: 'history_unavailable' });
  if (walletsOnDevice >= YOUR_DEVICE_WALLET_LIMIT) {
    return res.json({ status: 'review', reason: 'many_wallets_one_device' });
  }

  // 6. The claim itself. Different public and local IP countries on a device
  //    that already carries another wallet is the masked-network shape
  //    (local_ip is null on the History fallback).
  const countriesDiffer = Boolean(
    risk.local_ip?.country && risk.public_ip?.country
      && risk.local_ip.country !== risk.public_ip.country
  );
  if (band(risk.risk_score) === 'Dangerous' || (countriesDiffer && walletsOnDevice > 1)) {
    return res.json({ status: 'verify', reason: 'risk_signals' });
  }

  // A clean claim, a clean wallet and no wallet cluster: pay out.
  return grantAirdrop(walletAddress, res);
});