3 files changed, 104 insertions, 10 deletions
diff --git a/Core/Encoder/BasePasswordEncoder.php b/Core/Encoder/BasePasswordEncoder.php
index ae1c7d4..c26c9ce 100644
--- a/Core/Encoder/BasePasswordEncoder.php
+++ b/Core/Encoder/BasePasswordEncoder.php
@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\Security\Core\Encoder;
 
+use Symfony\Component\Security\Core\Util\StringUtils;
+
 /**
  * BasePasswordEncoder is the base class for all password encoders.
  *
@@ -50,6 +52,8 @@ abstract class BasePasswordEncoder implements PasswordEncoderInterface
      * @param string $salt     the salt to be used
      *
      * @return string a merged password and salt
+     *
+     * @throws \InvalidArgumentException
      */
     protected function mergePasswordAndSalt($password, $salt)
     {
@@ -77,15 +81,6 @@ abstract class BasePasswordEncoder implements PasswordEncoderInterface
      */
     protected function comparePasswords($password1, $password2)
     {
-        if (strlen($password1) !== strlen($password2)) {
-            return false;
-        }
-
-        $result = 0;
-        for ($i = 0; $i < strlen($password1); $i++) {
-            $result |= ord($password1[$i]) ^ ord($password2[$i]);
-        }
-
-        return 0 === $result;
+        return StringUtils::equals($password1, $password2);
     }
 }
diff --git a/Core/Encoder/EncoderFactory.php b/Core/Encoder/EncoderFactory.php
index 9429441..8bad61f 100644
--- a/Core/Encoder/EncoderFactory.php
+++ b/Core/Encoder/EncoderFactory.php
@@ -51,6 +51,8 @@ class EncoderFactory implements EncoderFactoryInterface
      * @param array $config
      *
      * @return PasswordEncoderInterface
+     *
+     * @throws \InvalidArgumentException
      */
     private function createEncoder(array $config)
     {
diff --git a/Core/Encoder/Pbkdf2PasswordEncoder.php b/Core/Encoder/Pbkdf2PasswordEncoder.php
new file mode 100644
index 0000000..656545f
--- /dev/null
+++ b/Core/Encoder/Pbkdf2PasswordEncoder.php
@@ -0,0 +1,97 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Security\Core\Encoder;
+
+/**
+ * Pbkdf2PasswordEncoder uses the PBKDF2 (Password-Based Key Derivation Function 2).
+ *
+ * Providing a high level of Cryptographic security,
+ *  PBKDF2 is recommended by the National Institute of Standards and Technology (NIST).
+ *
+ * But also warrants a warning, using PBKDF2 (with a high number of iterations) slows down the process.
+ * PBKDF2 should be used with caution and care.
+ *
+ * @author Sebastiaan Stok <s.stok@rollerscapes.net>
+ * @author Andrew Johnson
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class Pbkdf2PasswordEncoder extends BasePasswordEncoder
+{
+    private $algorithm;
+    private $encodeHashAsBase64;
+    private $iterations;
+    private $length;
+
+    /**
+     * Constructor.
+     *
+     * @param string  $algorithm          The digest algorithm to use
+     * @param Boolean $encodeHashAsBase64 Whether to base64 encode the password hash
+     * @param integer $iterations         The number of iterations to use to stretch the password hash
+     * @param integer $length             Length of derived key to create
+     */
+    public function __construct($algorithm = 'sha512', $encodeHashAsBase64 = true, $iterations = 1000, $length = 40)
+    {
+        $this->algorithm = $algorithm;
+        $this->encodeHashAsBase64 = $encodeHashAsBase64;
+        $this->iterations = $iterations;
+        $this->length = $length;
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @throws \LogicException when the algorithm is not supported
+     */
+    public function encodePassword($raw, $salt)
+    {
+        if (!in_array($this->algorithm, hash_algos(), true)) {
+            throw new \LogicException(sprintf('The algorithm "%s" is not supported.', $this->algorithm));
+        }
+
+        if (function_exists('hash_pbkdf2')) {
+            $digest = hash_pbkdf2($this->algorithm, $raw, $salt, $this->iterations, $this->length, true);
+        } else {
+            $digest = $this->hashPbkdf2($this->algorithm, $raw, $salt, $this->iterations, $this->length);
+        }
+
+        return $this->encodeHashAsBase64 ? base64_encode($digest) : bin2hex($digest);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isPasswordValid($encoded, $raw, $salt)
+    {
+        return $this->comparePasswords($encoded, $this->encodePassword($raw, $salt));
+    }
+
+    private function hashPbkdf2($algorithm, $password, $salt, $iterations, $length = 0)
+    {
+        // Number of blocks needed to create the derived key
+        $blocks = ceil($length / strlen(hash($algorithm, null, true)));
+        $digest = '';
+
+        for ($i = 1; $i <= $blocks; $i++) {
+            $ib = $block = hash_hmac($algorithm, $salt . pack('N', $i), $password, true);
+
+            // Iterations
+            for ($j = 1; $j < $iterations; $j++) {
+                $ib ^= ($block = hash_hmac($algorithm, $block, $password, true));
+            }
+
+            $digest .= $ib;
+        }
+
+        return substr($digest, 0, $this->length);
+    }
+}