diff options
| -rw-r--r-- | Authentication/JWT.php | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/Authentication/JWT.php b/Authentication/JWT.php index cd72a74..771f223 100644 --- a/Authentication/JWT.php +++ b/Authentication/JWT.php @@ -26,6 +26,28 @@ */ class JWT { + + /** + * Returns just the header portion of the jwt. This allows + * you to determine which key should be used to verify + * the jwt, using the "kid" field + * + * @param string $jwt + * + * @return object The JWT's header object, with fields "typ","alg", and optionally "kid" + */ + public static function decodeHeader($jwt) { + $tks = explode('.', $jwt); + if (count($tks) != 3) { + throw new UnexpectedValueException('Wrong number of segments'); + } + list($headb64, $bodyb64, $cryptob64) = $tks; + if (null === ($header = JWT::jsonDecode(JWT::urlsafeB64Decode($headb64)))) { + throw new UnexpectedValueException('Invalid segment encoding'); + } + return $header; + } + /** * Decodes a JWT string into a PHP object. * @@ -117,6 +139,7 @@ class JWT if (empty($methods[$method])) { throw new DomainException('Algorithm not supported'); } + return hash_hmac($methods[$method], $msg, $key, true); } |