source: sourcecode/system/libraries/Sha1.php @ 1

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package             CodeIgniter
 * @author              ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2008 - 2011, 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_SHA1 {

        public function __construct()
        {
                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; $i < count($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 */