<?php
/*
* Enano - an open-source CMS capable of wiki functions, Drupal-like sidebar blocks, and everything in between
* Copyright (C) 2006-2009 Dan Fuhry
* diffiehellman.php - Diffie Hellman key exchange and supporting functions
*
* This program is Free Software; you can redistribute and/or modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.
*/
/**
* EnanoMath GMP backend
*/
class EnanoMath_GMP
{
var $api = 'GMP';
/**
* Initializes a number to a GMP integer.
* @param string String representation of the number
* @param int Base the number is currently in, defaults to 10
* @return resource
*/
function init($int, $base = 10)
{
return ( is_resource($int) || (is_object($int) && $int instanceof \GMP) ) ? $int : gmp_init($int, $base);
}
/**
* Converts a number from a GMP integer to a string
* @param resource
* @param int Base, default is 10
* @return string
*/
function str($int, $base = 10)
{
return ( is_string($int) ) ? $int : gmp_strval($int, $base);
}
/**
* Converts a number between bases.
* @param resource BigInt to convert
* @param int Base to convert from
* @param int Base to convert to
*/
function basecon($int, $from, $to)
{
return $this->init(gmp_strval(gmp_init($this->str($int), $from), $to));
}
/**
* Generates a random integer.
* @param int Length
* @return resource
*/
function random($len)
{
return gmp_random($len / 8);
}
/**
* Powmod operation (calculates (a ^ b) mod m)
* @param resource a
* @param resource b
* @param resource m
* @return resource
*/
function powmod($a, $b, $m)
{
$a = $this->init($a);
$b = $this->init($b);
$m = $this->init($m);
return ( function_exists('gmp_powm') ) ? gmp_powm($a, $b, $m) : gmp_mod(gmp_pow($a, $b), $m);
}
}
/**
* EnanoMath big_int backend
*/
class EnanoMath_BigInt
{
var $api = 'big_int';
/**
* Initializes a number to a BigInt integer.
* @param string String representation of the number
* @param int Base the number is in, defaults to 10
* @return resource
*/
function init($int, $base = 10)
{
return (is_resource($int)) ? $int : bi_from_str($int, $base);
}
/**
* Converts a number from a BigInt integer to a string
* @param resource
* @param int Base, default is 10
* @return string
*/
function str($int, $base = 10)
{
return ( is_string($int) ) ? $int : bi_to_str($int, $base);
}
/**
* Generates a random integer
* @param int Length (bits)
* @return resource
*/
function random($len)
{
return bi_rand($len);
}
/**
* Converts a number between bases.
* @param resource BigInt to convert
* @param int Base to convert from
* @param int Base to convert to
*/
function basecon($int, $from, $to)
{
return bi_base_convert($this->str($int, $from), $from, $to);
}
/**
* Powmod operation (calculates (a ^ b) mod m)
* @param resource a
* @param resource b
* @param resource m
* @return resource
*/
function powmod($a, $b, $m)
{
$a = $this->init($a);
$b = $this->init($b);
$m = $this->init($m);
return bi_powmod($a, $b, $m);
}
}
/**
* EnanoMath BCMath backend
*/
class EnanoMath_BCMath
{
var $api = 'BCMath';
/**
* Initializes a number to a BCMath integer.
* @param string String representation of the number
* @param int Base the number is in, defaults to 10
* @return resource
*/
function init($int, $base = 10)
{
return $this->basecon($int, $base, 10);
}
/**
* Converts a number from a BCMath integer to a string
* @param resource
* @param int Base, default is 10
* @return string
*/
function str($res)
{
return ( is_string($res) ) ? $res : strval($this->basecon($res, 10, $base));
}
/**
* Generates a random integer
* @param int Length in bits
* @return resource
*/
function random($len)
{
$len = 4 * $len;
$chars = '0123456789abcdef';
$ret = '';
for ( $i = 0; $i < $len; $i++ )
{
$chid = mt_rand ( 0, strlen($chars) - 1 );
$chr = $chars{$chid};
$ret .= $chr;
}
return $this->basecon($this->init($ret), 16, 10);
}
/**
* Converts a number between bases.
* @param resource BigInt to convert
* @param int Base to convert from
* @param int Base to convert to
*/
function basecon($int, $from, $to)
{
if ( $from != 10 )
$int = $this->_bcmath_base2dec($int, $from);
if ( $to != 10 )
$int = $this->_bcmath_dec2base($int, $to);
return $int;
}
/**
* Powmod operation (calculates (a ^ b) mod m)
* @param resource a
* @param resource b
* @param resource m
* @return resource
*/
function powmod($a, $b, $m)
{
$a = $this->init($a);
$b = $this->init($b);
$m = $this->init($m);
return ( function_exists('bcpowmod') ) ? bcpowmod($a, $b, $m) : bcmod( bcpow($a, $b), $m );
}
// from us.php.net/bc:
// convert a decimal value to any other base value
function _bcmath_dec2base($dec,$base,$digits=FALSE) {
if($base<2 or $base>256) die("Invalid Base: ".$base);
bcscale(0);
$value="";
if(!$digits) $digits=$this->_bcmath_digits($base);
while($dec>$base-1) {
$rest=bcmod($dec,$base);
$dec=bcdiv($dec,$base);
$value=$digits[$rest].$value;
}
$value=$digits[intval($dec)].$value;
return (string) $value;
}
// convert another base value to its decimal value
function _bcmath_base2dec($value,$base,$digits=FALSE) {
if($base<2 or $base>256) die("Invalid Base: ".$base);
bcscale(0);
if($base<37) $value=strtolower($value);
if(!$digits) $digits=$this->_bcmath_digits($base);
$size=strlen($value);
$dec="0";
for($loop=0;$loop<$size;$loop++) {
$element=strpos($digits,$value[$loop]);
$power=bcpow($base,$size-$loop-1);
$dec=bcadd($dec,bcmul($element,$power));
}
return (string) $dec;
}
function _bcmath_digits($base) {
if($base>64) {
$digits="";
for($loop=0;$loop<256;$loop++) {
$digits.=chr($loop);
}
} else {
$digits ="0123456789abcdefghijklmnopqrstuvwxyz";
$digits.="ABCDEFGHIJKLMNOPQRSTUVWXYZ-_";
}
$digits=substr($digits,0,$base);
return (string) $digits;
}
}
/**
* Creates a new math object based on what libraries are available.
* @return object
*/
function enanomath_create()
{
if ( function_exists('gmp_init') )
return new EnanoMath_GMP();
else if ( function_exists('bi_from_str') )
return new EnanoMath_BigInt();
else if ( function_exists('bcadd') )
return new EnanoMath_BCMath();
else
throw new Exception('dh_err_not_supported');
}
?>