add methods to decrypt return data from router

[GitHub/Stricted/speedport-hybrid-php-api.git] / CryptLib / Core / BigMath / PHPMath.php

diff --git a/CryptLib/Core/BigMath/PHPMath.php b/CryptLib/Core/BigMath/PHPMath.php
new file mode 100644 (file)
index 0000000..10bb2c5
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+++ b/CryptLib/Core/BigMath/PHPMath.php
@@ -0,0 +1,170 @@
+<?php
+/**
+ * A class for arbitrary precision math functions implemented in PHP
+ *
+ * PHP version 5.3
+ *
+ * @category   PHPCryptLib
+ * @package    Core
+ * @subpackage BigMath
+ * @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\Core\BigMath;
+
+use CryptLib\Core\BaseConverter;
+
+/**
+ * A class for arbitrary precision math functions implemented in PHP
+ *
+ * @category   PHPCryptLib
+ * @package    Core
+ * @subpackage BigMath
+ */
+class PHPMath extends \CryptLib\Core\BigMath {
+
+    /**
+     * Add two numbers together
+     *
+     * @param string $left  The left argument
+     * @param string $right The right argument
+     *
+     * @return A base-10 string of the sum of the two arguments
+     */
+    public function add($left, $right) {
+        if (empty($left)) {
+            return $right;
+        } elseif (empty($right)) {
+            return $left;
+        }
+        $negative = '';
+        if ($left[0] == '-' && $right[0] == '-') {
+            $negative = '-';
+            $left     = substr($left, 1);
+            $right    = substr($right, 1);
+        } elseif ($left[0] == '-') {
+            return $this->subtract($right, substr($left, 1));
+        } elseif ($right[0] == '-') {
+            return $this->subtract($left, substr($right, 1));
+        }
+        $left   = $this->normalize($left);
+        $right  = $this->normalize($right);
+        $result = BaseConverter::convertFromBinary(
+            $this->addBinary($left, $right),
+            '0123456789'
+        );
+        return $negative . $result;
+    }
+
+    /**
+     * Subtract two numbers
+     *
+     * @param string $left  The left argument
+     * @param string $right The right argument
+     *
+     * @return A base-10 string of the difference of the two arguments
+     */
+    public function subtract($left, $right) {
+        if (empty($left)) {
+            return $right;
+        } elseif (empty($right)) {
+            return $left;
+        } elseif ($right[0] == '-') {
+            return $this->add($left, substr($right, 1));
+        } elseif ($left[0] == '-') {
+            return '-' . $this->add(ltrim($left, '-'), $right);
+        }
+        $left    = $this->normalize($left);
+        $right   = $this->normalize($right);
+        $results = $this->subtractBinary($left, $right);
+        $result  = BaseConverter::convertFromBinary($results[1], '0123456789');
+        return $results[0] . $result;
+    }
+
+    /**
+     * Add two binary strings together
+     *
+     * @param string $left  The left argument
+     * @param string $right The right argument
+     *
+     * @return string The binary result
+     */
+    protected function addBinary($left, $right) {
+        $len    = max(strlen($left), strlen($right));
+        $left   = str_pad($left, $len, chr(0), STR_PAD_LEFT);
+        $right  = str_pad($right, $len, chr(0), STR_PAD_LEFT);
+        $result = '';
+        $carry  = 0;
+        for ($i = 0; $i < $len; $i++) {
+            $sum     = ord($left[$len - $i - 1])
+                 + ord($right[$len - $i - 1])
+                 + $carry;
+            $result .= chr($sum % 256);
+            $carry   = $sum >> 8;
+        }
+        while ($carry) {
+            $result .= chr($carry % 256);
+            $carry >>= 8;
+        }
+        return strrev($result);
+    }
+
+    /**
+     * Subtract two binary strings using 256's compliment
+     *
+     * @param string $left  The left argument
+     * @param string $right The right argument
+     *
+     * @return string The binary result
+     */
+    protected function subtractBinary($left, $right) {
+        $len    = max(strlen($left), strlen($right));
+        $left   = str_pad($left, $len, chr(0), STR_PAD_LEFT);
+        $right  = str_pad($right, $len, chr(0), STR_PAD_LEFT);
+        $right  = $this->compliment($right);
+        $result = $this->addBinary($left, $right);
+        if (strlen($result) > $len) {
+            // Positive Result
+            $carry  = substr($result, 0, -1 * $len);
+            $result = substr($result, strlen($carry));
+            return array(
+                '',
+                $this->addBinary($result, $carry)
+            );
+        }
+        return array('-', $this->compliment($result));
+    }
+
+    /**
+     * Take the 256 base compliment
+     *
+     * @param string $string The binary string to compliment
+     *
+     * @return string The complimented string
+     */
+    protected function compliment($string) {
+        $result = '';
+        $len    = strlen($string);
+        for ($i = 0; $i < $len; $i++) {
+            $result .= chr(255 - ord($string[$i]));
+        }
+        return $result;
+    }
+
+    /**
+     * Transform a string number into a binary string using base autodetection
+     *
+     * @param string $string The string to transform
+     *
+     * @return string The binary transformed number
+     */
+    protected function normalize($string) {
+        return BaseConverter::convertToBinary(
+            $string,
+            '0123456789'
+        );
+    }
+
+}
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