AgeCheck PHP SDK (agecheck/php)

Server-side SDK for AgeCheck gate policy and JWT verification.

Features

• Verify AgeCheck JWTs signed with ES256
• Deployment mode: production or demo
• Enforce minimum age tier (N+, not capped at 21+)
• Require session binding (vc.credentialSubject.session)
• Raise gate from edge header (X-Age-Gate: true) in production, or always gate in demo deployment mode
• Create and verify signed verification cookies
• Resolve verification keys from deployment-mode JWKS (agecheck.me for production, demo.agecheck.me for demo)
• Cache JWKS with TTL and stale-cache fallback

Install

composer require agecheck/php

Requirements:

• PHP 8.1+

Quickstart: see /Quickstart.md.

Core usage

<?php

declare(strict_types=1);

use AgeCheck\Config;
use AgeCheck\Gate;
use AgeCheck\Verifier;

$config = new Config([
    'hmacSecret' => 'YOUR_32_BYTE_SECRET',
    'deploymentMode' => Config::DEPLOYMENT_PRODUCTION, // production | demo
    'requiredAge' => 18,
    'cookieTtl' => 86400, // seconds; hostmaster-controlled (e.g. 31536000 for 1 year)
    // Defaults are pinned to AgeCheck issuer/JWKS unless explicitly opted in.
    'allowCustomIssuer' => false,
    'gateHeaderName' => 'X-Age-Gate',
    'gateHeaderRequiredValue' => 'true',
]);

$gate = new Gate($config);
$verifier = new Verifier($config);

if ($gate->isGateRequired()) {
    $result = $verifier->verify($jwt);

    if (!$result->isOk()) {
        // deny
    }
}

Easy AgeGate Option

You can render gate HTML with either:

• easyAgeGate: true using easy-agegate.min.js, or
• easyAgeGate: false using plain agegate.min.js (full custom UI flow)

<?php

declare(strict_types=1);

use AgeCheck\Gate;

$gate = new Gate($config);

echo $gate->renderGatePage([
    'redirect' => '/protected',
    'easyAgeGate' => true,
    'easyAgeGateOptions' => [
        'title' => 'Age Restricted Content',
        'subtitle' => 'Please confirm your age anonymously using AgeCheck.me.',
        'verifyButtonText' => 'Verify Now',
        'logoUrl' => 'https://your-cdn/logo.svg', // optional
    ],
]);

Cookie helpers

<?php

declare(strict_types=1);

use AgeCheck\Gate;

$gate = new Gate($config);

if ($result->isOk() && is_array($result->claims())) {
    $gate->markVerified($result->claims());
}

Use Gate::isVerified() on protected routes to validate the signed cookie.

Signed cookie payload is minimal and stateless:

{ "verified": true, "exp": 1700000000, "level": "18+" }

You can also set the cookie through a provider-agnostic assertion boundary:

use AgeCheck\VerificationAssertion;

$assertion = VerificationAssertion::verified('agecheck', '18+', time(), 'passkey');
$gate->markVerifiedFromVerificationAssertion($assertion);

Provider integration

Hostmasters can run multiple providers side-by-side and still keep one cookie/session contract, matching the Node SDK provider-agnostic pattern.

use AgeCheck\Provider;

$expectedSession = $body['payload']['agegateway_session'] ?? null;
if (!is_string($expectedSession) || $expectedSession === '') {
    // deny
}

if (($body['provider'] ?? 'agecheck') === 'agecheck') {
    $normalized = Provider::verifyAgeCheckCredential($verifier, $body['jwt'] ?? '', $expectedSession);
} else {
    $external = $providerService->verify($body);
    $normalized = Provider::normalizeExternalProviderAssertion($external, $expectedSession);
}

if (($normalized['verified'] ?? null) !== true) {
    // deny (see $normalized['code'])
}

Provider::applyProviderAssertionCookie($gate, $normalized);

All providers converge to one assertion boundary (provider, verified, level, session, verifiedAtUnix), which keeps cookie issuance and protected-route enforcement consistent.

Session rules:

• payload.agegateway_session is required
• session must be a UUID
• provider assertion session must match payload.agegateway_session

Provider metadata fields (optional):

• verificationType: passkey | oid4vp | other
• evidenceType: webauthn_assertion | sd_jwt | zk_attestation | other
• providerTransactionId: provider transaction/reference id
• loa: level of assurance string

Security notes

• Backend enforcement remains authoritative; browser callbacks alone are not trusted.
• Require session binding in verification (payload.agegateway_session must equal vc.credentialSubject.session).
• Use edge policy to set X-Age-Gate: true where gate is legally required.
• Use HTTPS JWKS only. Defaults are mode-specific:
  • production: https://agecheck.me/.well-known/jwks.json
  • demo: https://demo.agecheck.me/.well-known/jwks.json with production JWKS fallback for mixed demo/prod acceptance
• Custom issuer/JWKS overrides are disabled by default. Enable with allowCustomIssuer=true only when intentional.

Standardized error codes

Verifier and provider helpers emit stable error codes such as:

• invalid_input
• invalid_issuer
• invalid_credential
• invalid_age_tier
• insufficient_age_tier
• session_binding_required
• session_binding_mismatch
• token_expired
• token_not_yet_valid
• invalid_signature
• unknown_key_id
• verify_failed

Troubleshooting

If verify responses include:

{
  "verified": false,
  "code": "verify_failed",
  "error": "Failed to issue verification cookie"
}

common causes are:

• hmacSecret missing in runtime config or shorter than 32 bytes
• malformed verification assertion level (must be N+, for example 18+)
• custom endpoint logic bypassing Gate/Provider helpers for cookie issuance

Examples

See examples/:

• examples/protected_index.php
• examples/agecheck_gate.php
• examples/ageverify_api.php
• examples/provider_verify_api.php
• examples/session_api.php
• examples/session_reset_api.php

examples/protected_index.php mirrors the Node reference behavior:

• server-side gate enforcement
• restricted page rendering only after cookie validation
• signed-cookie TTL countdown and reset action

License

Apache-2.0