// kit 01

PQC Toolkit

Production-ready post-quantum crypto. Pick stack, pick primitive, copy the code.

$ pqc_jwt.php
L3
PHP 
1<?php
2declare(strict_types=1);
3require __DIR__ . '/PqcSign.php';   // FFI wrapper for ML-DSA-65 via liboqs
4 
5final class HybridJwt
6{
7    public function __construct(
8        private string $edPriv,
9        private string $edPub,
10        private string $pqPriv,
11        private string $pqPub,
12        private PqcSign $pq,
13    ) {}
14 
15    public function issue(array $claims): string
16    {
17        $header  = ['alg' => 'EdDSA+ML-DSA-65', 'typ' => 'JWT-HYBRID'];
18        $payload = $claims + ['iat' => time()];
19        $hb = self::b64(json_encode($header,  JSON_UNESCAPED_SLASHES));
20        $pb = self::b64(json_encode($payload, JSON_UNESCAPED_SLASHES));
21        $msg = "$hb.$pb";
22        $sigEd = sodium_crypto_sign_detached($msg, $this->edPriv);
23        $sigPq = $this->pq->sign($msg, $this->pqPriv);
24        return "$msg." . self::b64($sigEd) . '.' . self::b64($sigPq);
25    }
26 
27    public function verify(string $token): array | null
28    {
29        $parts = explode('.', $token);
30        if (count($parts) !== 4) return null;
31        [$hb, $pb, $sed, $spq] = $parts;
32        $msg = "$hb.$pb";
33        if (!sodium_crypto_sign_verify_detached(self::ub64($sed), $msg, $this->edPub)) return null;
34        if (!$this->pq->verify($msg, self::ub64($spq), $this->pqPub)) return null;
35        return json_decode(self::ub64($pb), true);
36    }
37 
38    private static function b64(string $b): string  { return rtrim(strtr(base64_encode($b), '+/', '-_'), '='); }
39    private static function ub64(string $s): string { return base64_decode(strtr($s, '-_', '+/')); }
40}
KEY SIZE
1952 B pub
SIG / CT
3293 B sig
NIST LEVEL
L3
NOTES

Hybrid JWT verification in PHP using libsodium + FFI to liboqs.

  • Verification cost via FFI is ~2 ms.
  • Cache the parsed PQ public key as a typed FFI array via APCu.
  • Verify the token once at the gateway and pass a small claim downstream.