/**
* Turn a binary back into a long
* @param string $b
* @return integer
* @url http://openidenabled.com Borrowed from PHP-OpenID
*/
function long($b)
{
$bytes = array_merge(unpack('C*', $b));
$n = 0;
foreach ($bytes as $byte) {
$n = bmmul($n, bmpow(2, 8));
$n = bmadd($n, $byte);
}
return $n;
}
function bmpowmod($value, $exponent, $mod)
{
if (function_exists('bcpowmod')) {
return bcpowmod($value, $exponent, $mod);
}
if (function_exists('gmp_powm')) {
return gmp_strval(gmp_powm($value, $exponent, $mod));
}
$r = '';
while ($exponent != '0') {
$t = bmmod($exponent, '4096');
$r = substr("000000000000" . decbin(intval($t)), -12) . $r;
$exponent = bmdiv($exponent, '4096');
}
$r = preg_replace("!^0+!", "", $r);
if ($r == '') {
$r = '0';
}
$value = bmmod($value, $mod);
$erb = strrev($r);
$q = '1';
$a[0] = $value;
for ($i = 1; $i < strlen($erb); $i++) {
$a[$i] = bmmod(bmmul($a[$i - 1], $a[$i - 1]), $mod);
}
for ($i = 0; $i < strlen($erb); $i++) {
if ($erb[$i] == "1") {
$q = bmmod(bmmul($q, $a[$i]), $mod);
}
}
return $q;
}
