add methods to decrypt return data from router

[GitHub/Stricted/speedport-hybrid-php-api.git] / CryptLib / Key / Derivation / KDF / KDF1.php

diff --git a/CryptLib/Key/Derivation/KDF/KDF1.php b/CryptLib/Key/Derivation/KDF/KDF1.php
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+++ b/CryptLib/Key/Derivation/KDF/KDF1.php
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+<?php
+/**
+ * An implementation of the RFC 10833-2 KDF1 Standard key derivation function
+ *
+ * PHP version 5.3
+ *
+ * @category   PHPCryptLib
+ * @package    Key
+ * @subpackage Derivation
+ * @author     Anthony Ferrara <ircmaxell@ircmaxell.com>
+ * @copyright  2011 The Authors
+ * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
+ * @version    Build @@version@@
+ */
+
+namespace CryptLib\Key\Derivation\KDF;
+
+use CryptLib\Hash\Hash;
+
+/**
+ * An implementation of the RFC 10833-2 KDF1 Standard key derivation function
+ *
+ * @category   PHPCryptLib
+ * @package    Key
+ * @subpackage Derivation
+ * @author     Anthony Ferrara <ircmaxell@ircmaxell.com>
+ */
+class KDF1
+    extends \CryptLib\Key\Derivation\AbstractDerivation
+    implements \CryptLib\Key\Derivation\KDF
+{
+
+    /**
+     * Derive a key of the specified length based on the inputted secret
+     *
+     * @param string $secret The secret to base the key on
+     * @param int    $length The length of the key to derive
+     * @param string $other  Additional data to append to the key
+     *
+     * @return string The generated key
+     */
+    public function derive($secret, $length, $other = '') {
+        $size = Hash::getHashSize($this->hash);
+        $len  = ceil($length / $size);
+        $res  = '';
+        for ($i = 0; $i < $len; $i++) {
+            $tmp  = pack('N', $i);
+            $res .= hash($this->hash, $secret . $tmp . $other, true);
+        }
+        return substr($res, 0, $length);
+    }
+
+}
+