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<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**

 * CodeIgniter

 *

 * An open source application development framework for PHP 4.3.2 or newer

 *

 * @package		CodeIgniter

 * @author		ExpressionEngine Dev Team

 * @copyright	Copyright (c) 2008, EllisLab, Inc.

 * @license		http://codeigniter.com/user_guide/license.html

 * @link		http://codeigniter.com

 * @since		Version 1.0

 * @filesource

 */

// ------------------------------------------------------------------------

/**

 * SHA1 Encoding Class

 *

 * Purpose: Provides 160 bit hashing using The Secure Hash Algorithm

 * developed at the National Institute of Standards and Technology. The 40

 * character SHA1 message hash is computationally infeasible to crack.

 *

 * This class is a fallback for servers that are not running PHP greater than

 * 4.3, or do not have the MHASH library.

 *

 * This class is based on two scripts:

 *

 * Marcus Campbell's PHP implementation (GNU license)

 * http://www.tecknik.net/sha-1/

 *

 * ...which is based on Paul Johnston's JavaScript version

 * (BSD license). http://pajhome.org.uk/

 *

 * I encapsulated the functions and wrote one additional method to fix

 * a hex conversion bug. - Rick Ellis

 *

 * @package		CodeIgniter

 * @subpackage	Libraries

 * @category	Encryption

 * @author		ExpressionEngine Dev Team

 * @link		http://codeigniter.com/user_guide/general/encryption.html

 */

class CI_SHA {

	function CI_SHA()

	{

		log_message('debug', "SHA1 Class Initialized");

	}

	/**

	 * Generate the Hash

	 *

	 * @access	public

	 * @param	string

	 * @return	string

	 */

	function generate($str)

	{

		$n = ((strlen($str) + 8) >> 6) + 1;

		for ($i = 0; $i < $n * 16; $i++)

		{

			$x[$i] = 0;

		}

		for ($i = 0; $i < strlen($str); $i++)

		{

			$x[$i >> 2] |= ord(substr($str, $i, 1)) << (24 - ($i % 4) * 8);

		}

		$x[$i >> 2] |= 0x80 << (24 - ($i % 4) * 8);

		$x[$n * 16 - 1] = strlen($str) * 8;

		$a =  1732584193;

		$b = -271733879;

		$c = -1732584194;

		$d =  271733878;

		$e = -1009589776;

		for ($i = 0; $i < sizeof($x); $i += 16)

		{

			$olda = $a;

			$oldb = $b;

			$oldc = $c;

			$oldd = $d;

			$olde = $e;

			for($j = 0; $j < 80; $j++)

			{

				if ($j < 16)

				{

					$w[$j] = $x[$i + $j];

				}

				else

				{

					$w[$j] = $this->_rol($w[$j - 3] ^ $w[$j - 8] ^ $w[$j - 14] ^ $w[$j - 16], 1);

				}

				$t = $this->_safe_add($this->_safe_add($this->_rol($a, 5), $this->_ft($j, $b, $c, $d)), $this->_safe_add($this->_safe_add($e, $w[$j]), $this->_kt($j)));

				$e = $d;

				$d = $c;

				$c = $this->_rol($b, 30);

				$b = $a;

				$a = $t;

			}

			$a = $this->_safe_add($a, $olda);

			$b = $this->_safe_add($b, $oldb);

			$c = $this->_safe_add($c, $oldc);

			$d = $this->_safe_add($d, $oldd);

			$e = $this->_safe_add($e, $olde);

		}

		return $this->_hex($a).$this->_hex($b).$this->_hex($c).$this->_hex($d).$this->_hex($e);

	}

	// --------------------------------------------------------------------

	/**

	 * Convert a decimal to hex

	 *

	 * @access	private

	 * @param	string

	 * @return	string

	 */

	function _hex($str)

	{

		$str = dechex($str);

		if (strlen($str) == 7)

		{

			$str = '0'.$str;

		}

		return $str;

	}

	// --------------------------------------------------------------------

	/**

	 *  Return result based on iteration

	 *

	 * @access	private

	 * @return	string

	 */

	function _ft($t, $b, $c, $d)

	{

		if ($t < 20)

			return ($b & $c) | ((~$b) & $d);

		if ($t < 40)

			return $b ^ $c ^ $d;

		if ($t < 60)

			return ($b & $c) | ($b & $d) | ($c & $d);

		return $b ^ $c ^ $d;

	}

	// --------------------------------------------------------------------

	/**

	 * Determine the additive constant

	 *

	 * @access	private

	 * @return	string

	 */

	function _kt($t)

	{

		if ($t < 20)

		{

			return 1518500249;

		}

		else if ($t < 40)

		{

			return 1859775393;

		}

		else if ($t < 60)

		{

			return -1894007588;

		}

		else

		{

			return -899497514;

		}

	}

	// --------------------------------------------------------------------

	/**

	 * Add integers, wrapping at 2^32

	 *

	 * @access	private

	 * @return	string

	 */

	function _safe_add($x, $y)

	{

		$lsw = ($x & 0xFFFF) + ($y & 0xFFFF);

		$msw = ($x >> 16) + ($y >> 16) + ($lsw >> 16);

		return ($msw << 16) | ($lsw & 0xFFFF);

	}

	// --------------------------------------------------------------------

	/**

	 * Bitwise rotate a 32-bit number

	 *

	 * @access	private

	 * @return	integer

	 */

	function _rol($num, $cnt)

	{

		return ($num << $cnt) | $this->_zero_fill($num, 32 - $cnt);

	}

	// --------------------------------------------------------------------

	/**

	 * Pad string with zero

	 *

	 * @access	private

	 * @return	string

	 */

	function _zero_fill($a, $b)

	{

		$bin = decbin($a);

		if (strlen($bin) < $b)

		{

			$bin = 0;

		}

		else

		{

			$bin = substr($bin, 0, strlen($bin) - $b);

		}

		for ($i=0; $i < $b; $i++)

		{

			$bin = "0".$bin;

		}

		return bindec($bin);

	}

}

// END CI_SHA

/* End of file Sha1.php */

/* Location: ./system/libraries/Sha1.php */