1 files changed, 173 insertions, 0 deletions
diff --git a/library/oauth2/src/OAuth2/Encryption/Jwt.php b/library/oauth2/src/OAuth2/Encryption/Jwt.php
new file mode 100644
index 000000000..ee576e643
--- /dev/null
+++ b/library/oauth2/src/OAuth2/Encryption/Jwt.php
@@ -0,0 +1,173 @@
+<?php
+
+namespace OAuth2\Encryption;
+
+/**
+ * @link https://github.com/F21/jwt
+ * @author F21
+ */
+class Jwt implements EncryptionInterface
+{
+    public function encode($payload, $key, $algo = 'HS256')
+    {
+        $header = $this->generateJwtHeader($payload, $algo);
+
+        $segments = array(
+            $this->urlSafeB64Encode(json_encode($header)),
+            $this->urlSafeB64Encode(json_encode($payload))
+        );
+
+        $signing_input = implode('.', $segments);
+
+        $signature = $this->sign($signing_input, $key, $algo);
+        $segments[] = $this->urlsafeB64Encode($signature);
+
+        return implode('.', $segments);
+    }
+
+    public function decode($jwt, $key = null, $allowedAlgorithms = true)
+    {
+        if (!strpos($jwt, '.')) {
+            return false;
+        }
+
+        $tks = explode('.', $jwt);
+
+        if (count($tks) != 3) {
+            return false;
+        }
+
+        list($headb64, $payloadb64, $cryptob64) = $tks;
+
+        if (null === ($header = json_decode($this->urlSafeB64Decode($headb64), true))) {
+            return false;
+        }
+
+        if (null === $payload = json_decode($this->urlSafeB64Decode($payloadb64), true)) {
+            return false;
+        }
+
+        $sig = $this->urlSafeB64Decode($cryptob64);
+
+        if ((bool) $allowedAlgorithms) {
+            if (!isset($header['alg'])) {
+                return false;
+            }
+
+            // check if bool arg supplied here to maintain BC
+            if (is_array($allowedAlgorithms) && !in_array($header['alg'], $allowedAlgorithms)) {
+                return false;
+            }
+
+            if (!$this->verifySignature($sig, "$headb64.$payloadb64", $key, $header['alg'])) {
+                return false;
+            }
+        }
+
+        return $payload;
+    }
+
+    private function verifySignature($signature, $input, $key, $algo = 'HS256')
+    {
+        // use constants when possible, for HipHop support
+        switch ($algo) {
+            case'HS256':
+            case'HS384':
+            case'HS512':
+                return $this->hash_equals(
+                    $this->sign($input, $key, $algo),
+                    $signature
+                );
+
+            case 'RS256':
+                return openssl_verify($input, $signature, $key, defined('OPENSSL_ALGO_SHA256') ? OPENSSL_ALGO_SHA256 : 'sha256')  === 1;
+
+            case 'RS384':
+                return @openssl_verify($input, $signature, $key, defined('OPENSSL_ALGO_SHA384') ? OPENSSL_ALGO_SHA384 : 'sha384') === 1;
+
+            case 'RS512':
+                return @openssl_verify($input, $signature, $key, defined('OPENSSL_ALGO_SHA512') ? OPENSSL_ALGO_SHA512 : 'sha512') === 1;
+
+            default:
+                throw new \InvalidArgumentException("Unsupported or invalid signing algorithm.");
+        }
+    }
+
+    private function sign($input, $key, $algo = 'HS256')
+    {
+        switch ($algo) {
+            case 'HS256':
+                return hash_hmac('sha256', $input, $key, true);
+
+            case 'HS384':
+                return hash_hmac('sha384', $input, $key, true);
+
+            case 'HS512':
+                return hash_hmac('sha512', $input, $key, true);
+
+            case 'RS256':
+                return $this->generateRSASignature($input, $key, defined('OPENSSL_ALGO_SHA256') ? OPENSSL_ALGO_SHA256 : 'sha256');
+
+            case 'RS384':
+                return $this->generateRSASignature($input, $key, defined('OPENSSL_ALGO_SHA384') ? OPENSSL_ALGO_SHA384 : 'sha384');
+
+            case 'RS512':
+                return $this->generateRSASignature($input, $key, defined('OPENSSL_ALGO_SHA512') ? OPENSSL_ALGO_SHA512 : 'sha512');
+
+            default:
+                throw new \Exception("Unsupported or invalid signing algorithm.");
+        }
+    }
+
+    private function generateRSASignature($input, $key, $algo)
+    {
+        if (!openssl_sign($input, $signature, $key, $algo)) {
+            throw new \Exception("Unable to sign data.");
+        }
+
+        return $signature;
+    }
+
+    public function urlSafeB64Encode($data)
+    {
+        $b64 = base64_encode($data);
+        $b64 = str_replace(array('+', '/', "\r", "\n", '='),
+                array('-', '_'),
+                $b64);
+
+        return $b64;
+    }
+
+    public function urlSafeB64Decode($b64)
+    {
+        $b64 = str_replace(array('-', '_'),
+                array('+', '/'),
+                $b64);
+
+        return base64_decode($b64);
+    }
+
+    /**
+     * Override to create a custom header
+     */
+    protected function generateJwtHeader($payload, $algorithm)
+    {
+        return array(
+            'typ' => 'JWT',
+            'alg' => $algorithm,
+        );
+    }
+
+    protected function hash_equals($a, $b)
+    {
+        if (function_exists('hash_equals')) {
+            return hash_equals($a, $b);
+        }
+        $diff = strlen($a) ^ strlen($b);
+        for ($i = 0; $i < strlen($a) && $i < strlen($b); $i++) {
+            $diff |= ord($a[$i]) ^ ord($b[$i]);
+        }
+
+        return $diff === 0;
+    }
+}