<?php
/**
* Crypt_RSA allows to do following operations:
* - key pair generation
* - encryption and decryption
* - signing and sign validation
*
* PHP versions 4 and 5
*
* LICENSE: This source file is subject to version 3.0 of the PHP license
* that is available through the world-wide-web at the following URI:
* http://www.php.net/license/3_0.txt. If you did not receive a copy of
* the PHP License and are unable to obtain it through the web, please
* send a note to license@php.net so we can mail you a copy immediately.
*
* @category Encryption
* @package Crypt_RSA
* @author Alexander Valyalkin <valyala@gmail.com>
* @copyright 2005, 2006 Alexander Valyalkin
* @license http://www.php.net/license/3_0.txt PHP License 3.0
* @version 1.2.0b
* @link http://pear.php.net/package/Crypt_RSA
*/
/**
* Crypt_RSA_Math_BigInt class.
*
* Provides set of math functions, which are used by Crypt_RSA package
* This class is a wrapper for big_int PECL extension,
* which could be loaded from http://pecl.php.net/packages/big_int
*
* @category Encryption
* @package Crypt_RSA
* @author Alexander Valyalkin <valyala@gmail.com>
* @copyright 2005, 2006 Alexander Valyalkin
* @license http://www.php.net/license/3_0.txt PHP License 3.0
* @link http://pear.php.net/package/Crypt_RSA
* @version @package_version@
* @access public
*/
class Crypt_RSA_Math_BigInt
{
/**
* error description
*
* @var string
* @access public
*/
var $errstr = '';
/**
* Crypt_RSA_Math_BigInt constructor.
* Checks an existance of big_int PECL math package.
* This package is available at http://pecl.php.net/packages/big_int
* On failure saves error description in $this->errstr
*
* @access public
*/
function Crypt_RSA_Math_BigInt()
{
if (!extension_loaded('big_int')) {
if (!@dl('big_int.' . PHP_SHLIB_SUFFIX) && !@dl('php_big_int.' . PHP_SHLIB_SUFFIX)) {
// cannot load big_int extension
$this->errstr = 'Crypt_RSA package requires big_int PECL package. ' .
'It is available at http://pecl.php.net/packages/big_int';
return;
}
}
// check version of big_int extension ( Crypt_RSA requires version 1.0.2 and higher )
if (!in_array('bi_info', get_extension_funcs('big_int'))) {
// there is no bi_info() function in versions, older than 1.0.2
$this->errstr = 'Crypt_RSA package requires big_int package version 1.0.2 and higher';
}
}
/**
* Transforms binary representation of large integer into its native form.
*
* Example of transformation:
* $str = "\x12\x34\x56\x78\x90";
* $num = 0x9078563412;
*
* @param string $str
* @return big_int resource
* @access public
*/
function bin2int($str)
{
return bi_unserialize($str);
}
/**
* Transforms large integer into binary representation.
*
* Example of transformation:
* $num = 0x9078563412;
* $str = "\x12\x34\x56\x78\x90";
*
* @param big_int resource $num
* @return string
* @access public
*/
function int2bin($num)
{
return bi_serialize($num);
}
/**
* Calculates pow($num, $pow) (mod $mod)
*
* @param big_int resource $num
* @param big_int resource $pow
* @param big_int resource $mod
* @return big_int resource
* @access public
*/
function powmod($num, $pow, $mod)
{
return bi_powmod($num, $pow, $mod);
}
/**
* Calculates $num1 * $num2
*
* @param big_int resource $num1
* @param big_int resource $num2
* @return big_int resource
* @access public
*/
function mul($num1, $num2)
{
return bi_mul($num1, $num2);
}
/**
* Calculates $num1 % $num2
*
* @param string $num1
* @param string $num2
* @return string
* @access public
*/
function mod($num1, $num2)
{
return bi_mod($num1, $num2);
}
/**
* Compares abs($num1) to abs($num2).
* Returns:
* -1, if abs($num1) < abs($num2)
* 0, if abs($num1) == abs($num2)
* 1, if abs($num1) > abs($num2)
*
* @param big_int resource $num1
* @param big_int resource $num2
* @return int
* @access public
*/
function cmpAbs($num1, $num2)
{
return bi_cmp_abs($num1, $num2);
}
/**
* Tests $num on primality. Returns true, if $num is strong pseudoprime.
* Else returns false.
*
* @param string $num
* @return bool
* @access private
*/
function isPrime($num)
{
return bi_is_prime($num) ? true : false;
}
/**
* Generates prime number with length $bits_cnt
* using $random_generator as random generator function.
*
* @param int $bits_cnt
* @param string $rnd_generator
* @access public
*/
function getPrime($bits_cnt, $random_generator)
{
$bytes_n = intval($bits_cnt / 8);
$bits_n = $bits_cnt % 8;
do {
$str = '';
for ($i = 0; $i < $bytes_n; $i++) {
$str .= chr(call_user_func($random_generator) & 0xff);
}
$n = call_user_func($random_generator) & 0xff;
$n |= 0x80;
$n >>= 8 - $bits_n;
$str .= chr($n);
$num = $this->bin2int($str);
// search for the next closest prime number after [$num]
$num = bi_next_prime($num);
} while ($this->bitLen($num) != $bits_cnt);
return $num;
}
/**
* Calculates $num - 1
*
* @param big_int resource $num
* @return big_int resource
* @access public
*/
function dec($num)
{
return bi_dec($num);
}
/**
* Returns true, if $num is equal to 1. Else returns false
*
* @param big_int resource $num
* @return bool
* @access public
*/
function isOne($num)
{
return bi_is_one($num);
}
/**
* Finds greatest common divider (GCD) of $num1 and $num2
*
* @param big_int resource $num1
* @param big_int resource $num2
* @return big_int resource
* @access public
*/
function GCD($num1, $num2)
{
return bi_gcd($num1, $num2);
}
/**
* Finds inverse number $inv for $num by modulus $mod, such as:
* $inv * $num = 1 (mod $mod)
*
* @param big_int resource $num
* @param big_int resource $mod
* @return big_int resource
* @access public
*/
function invmod($num, $mod)
{
return bi_invmod($num, $mod);
}
/**
* Returns bit length of number $num
*
* @param big_int resource $num
* @return int
* @access public
*/
function bitLen($num)
{
return bi_bit_len($num);
}
/**
* Calculates bitwise or of $num1 and $num2,
* starting from bit $start_pos for number $num1
*
* @param big_int resource $num1
* @param big_int resource $num2
* @param int $start_pos
* @return big_int resource
* @access public
*/
function bitOr($num1, $num2, $start_pos)
{
return bi_or($num1, $num2, $start_pos);
}
/**
* Returns part of number $num, starting at bit
* position $start with length $length
*
* @param big_int resource $num
* @param int start
* @param int length
* @return big_int resource
* @access public
*/
function subint($num, $start, $length)
{
return bi_subint($num, $start, $length);
}
/**
* Returns name of current wrapper
*
* @return string name of current wrapper
* @access public
*/
function getWrapperName()
{
return 'BigInt';
}
}
?>