/**
* powmod using bcmath extension
*/
function _powmodBcmath($x, $y, $mod)
{
if (function_exists('bcpowmod')) {
return bcpowmod($x, $y, $mod);
} else {
if (bccomp($y, 1) == 0) {
return bcmod($x, $mod);
} else {
if (bcmod($y, 2) == 0) {
return bcmod(bcpow(Security_DSA::_powmodBcmath($x, bcdiv($y, 2), $mod), 2), $mod);
} else {
return bcmod(bcmul($x, Security_DSA::_powmodBcmath($x, bcsub($y, 1), $mod)), $mod);
}
}
}
}
function auth()
{
if (empty($this->response['email'])) {
return false;
}
// FIXME: どの程度までチェックするのか？
if ($this->need_email) {
if (!strpos($this->response['email'], '@')) {
return false;
}
}
$message = $this->gen_message();
require_once LIB_DIR . 'DSA.php';
return Security_DSA::verify($message, $this->response['sig'], $this->regkeys);
}