/**
* invert using bcmath extension
*/
function _invertBcmath($x, $y)
{
while (bccomp($x, 0) < 0) {
$x = bcadd($x, $y);
}
$r = Security_DSA::_exgcdBcmath($x, $y);
if ($r[2] == 1) {
$a = $r[0];
while (bccomp($a, 0) < 0) {
$a = bcadd($a, $y);
}
return $a;
} else {
return false;
}
}
