add methods to decrypt return data from router

[GitHub/Stricted/speedport-hybrid-php-api.git] / CryptLib / Cipher / Block / Mode / CTR.php

diff --git a/CryptLib/Cipher/Block/Mode/CTR.php b/CryptLib/Cipher/Block/Mode/CTR.php
new file mode 100644 (file)
index 0000000..8c17e86
--- /dev/null
+++ b/CryptLib/Cipher/Block/Mode/CTR.php
@@ -0,0 +1,94 @@
+<?php
+/**
+ * The CTR (Counter) mode implementation
+ *
+ * PHP version 5.3
+ *
+ * @category   PHPCryptLib
+ * @package    Cipher
+ * @subpackage Block
+ * @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\Cipher\Block\Mode;
+
+use CryptLib\Core\BaseConverter;
+use CryptLib\Core\BigMath;
+
+/**
+ * The CTR (Counter) mode implementation
+ *
+ * @category   PHPCryptLib
+ * @package    Cipher
+ * @subpackage Block
+ * @author     Anthony Ferrara <ircmaxell@ircmaxell.com>
+ */
+
+class CTR extends \CryptLib\Cipher\Block\AbstractMode {
+
+    /**
+     * @var BigMath An instance of the BigMath library
+     */
+    protected $bigMath = null;
+
+    /**
+     * Build the instance of the cipher mode
+     *
+     * @param Cipher $cipher  The cipher to use for encryption/decryption
+     * @param string $initv   The initialization vector (empty if not needed)
+     * @param array  $options An array of mode-specific options
+     */
+    public function __construct(
+        \CryptLib\Cipher\Block\Cipher $cipher,
+        $initv,
+        array $options = array()
+    ) {
+        parent::__construct($cipher, $initv, $options);
+        $this->bigMath = BigMath::createFromServerConfiguration();
+    }
+
+    /**
+     * Reset the mode to start over (destroying any intermediate state)
+     *
+     * @return void
+     */
+    public function reset() {
+        $this->state = BaseConverter::ConvertFromBinary($this->initv, '0123456789');
+        $this->state = ltrim($this->state, '0');
+    }
+
+    /**
+     * Decrypt the data using the supplied key, cipher
+     *
+     * @param string $data The data to decrypt
+     *
+     * @return string The decrypted data
+     */
+    protected function decryptBlock($data) {
+        return $this->encryptBlock($data);
+    }
+
+    /**
+     * Encrypt the data using the supplied key, cipher
+     *
+     * @param string $data The data to encrypt
+     *
+     * @return string The encrypted data
+     */
+    protected function encryptBlock($data) {
+        $size        = $this->cipher->getBlockSize();
+        $state       = str_pad(
+            BaseConverter::convertToBinary($this->state, '0123456789'),
+            $size,
+            chr(0),
+            STR_PAD_LEFT
+        );
+        $stub        = $this->cipher->encryptBlock($state);
+        $this->state = $this->bigMath->add($this->state, 1);
+        return $stub ^ $data;
+    }
+
+}