web-token (JWT Framework)

Facts and the checks behind them

Nothing below is copied from documentation. The check content/libraries/verify/web-token-jwt-framework/run.sh ran web-token (JWT Framework) 4.2.3 in the container image php:8.5.11-cli-trixie on October 20, 2026; the page must match what it printed, and each fact lists those lines.

• JWS algorithms

  HS256HS384HS512RS256RS384RS512PS256PS384PS512ES256ES384ES512EdDSA

  HS, RS, PS and ES at 256/384/512 and EdDSA signed and verified; there are no ES256K or Ed25519 algorithm classes.

  Recorded by the check

  fact jws-algorithms = HS256, HS384, HS512, RS256, RS384, RS512, PS256, PS384, PS512, ES256, ES384, ES512, EdDSA
  evidence jws-algorithms: ES256K: class Jose\Component\Signature\Algorithm\ES256K exists: false
  evidence jws-algorithms: Ed25519: class Jose\Component\Signature\Algorithm\Ed25519 exists: false

• ES256 signature encoding

  raw

  ES256 signatures are 64 bytes of raw r‖s.

  Recorded by the check

  fact jws-ecdsa-encoding = raw

• DER signature inside a JWS

  rejected

  A DER-encoded ES256 signature makes verifyWithKey() return false.

  Recorded by the check

  fact jws-der-signature = rejected
  evidence jws-der-signature: false

• Algorithm allow-list

  required

  The AlgorithmManager is the allow-list: an RS256 token against a manager holding only ES256 failed with The algorithm "RS256" is not supported.

  Recorded by the check

  fact jwt-algorithm-allowlist = required
  evidence jwt-algorithm-allowlist: RS256 token with an AlgorithmManager holding only ES256: InvalidArgumentException: The algorithm "RS256" is not supported.

• Unsigned tokens (alg none)

  opt-in

  An unsigned token fails with The algorithm "none" is not supported. unless the None algorithm class is added to the manager.

  Recorded by the check

  fact jwt-alg-none = opt-in
  evidence jwt-alg-none: with an ES256 AlgorithmManager: InvalidArgumentException: The algorithm "none" is not supported.; a None algorithm class exists: true

• Public key used as an HMAC secret

  rejected

  With ES256 and HS256 both allowed, an HS256 token keyed with the PEM text failed against the EC JWK.

  Recorded by the check

  fact jwt-hmac-public-key = rejected
  evidence jwt-hmac-public-key: AlgorithmManager [ES256, HS256] with the EC JWK: false

• Curve checked against alg

  enforced

  Signing ES256 with a P-384 key succeeded, but the library's verifier rejected the result.

  Recorded by the check

  fact jwt-ecdsa-curve-check = enforced
  evidence jwt-ecdsa-curve-check: ES256 with a P-384 key, signing: ok; verifying: false

• Claims validated while decoding

  no

  JWSVerifier::verifyWithKey() returned true for a token expired an hour earlier; claims are checked by a separate ClaimCheckerManager.

  Recorded by the check

  fact jwt-claims-validated-on-decode = no
  evidence jwt-claims-validated-on-decode: JWSVerifier on a token expired an hour ago: ok

• Default clock skew

  0s

  ExpirationTimeChecker allows no drift unless given one: a token expired three seconds earlier was rejected.

  Recorded by the check

  fact jwt-clock-skew = 0s

• Expiry claim required

  no

  Without exp in the mandatory claims, a token lacking it passed; listing it raised MissingMandatoryClaimException.

  Recorded by the check

  fact jwt-exp-required = no
  evidence jwt-exp-required: ExpirationTimeChecker without exp: ok; with exp listed as mandatory: Jose\Component\Checker\MissingMandatoryClaimException: The following claims are mandatory: exp.

Usage

<?php
require 'vendor/autoload.php';

use Jose\Component\Checker\{ClaimCheckerManager, ExpirationTimeChecker, IssuerChecker};
use Jose\Component\Core\AlgorithmManager;
use Jose\Component\KeyManagement\JWKFactory;
use Jose\Component\Signature\Algorithm\ES256;
use Jose\Component\Signature\{JWSBuilder, JWSVerifier};
use Jose\Component\Signature\Serializer\CompactSerializer;

$jwk = JWKFactory::createECKey('P-256');
$algorithms = new AlgorithmManager([new ES256()]); // the allow-list
$payload = json_encode(['sub' => 'user-42', 'iss' => 'https://auth.example.com', 'exp' => time() + 600]);
$jws = (new JWSBuilder($algorithms))->create()->withPayload($payload)->addSignature($jwk, ['alg' => 'ES256'])->build();
$token = (new CompactSerializer())->serialize($jws, 0);

// The signature check does not look at claims: run the claim checkers as a second step.
$parsed = (new CompactSerializer())->unserialize($token);
$valid = (new JWSVerifier($algorithms))->verifyWithKey($parsed, $jwk->toPublic(), 0);
$clock = new class implements Psr\Clock\ClockInterface { public function now(): DateTimeImmutable { return new DateTimeImmutable(); } };
$claims = json_decode($parsed->getPayload(), true);
(new ClaimCheckerManager([new ExpirationTimeChecker($clock, 30), new IssuerChecker(['https://auth.example.com'])]))->check($claims, ['exp', 'iss']);
echo 'valid: ', var_export($valid, true), ', sub: ', $claims['sub'], "\n";