CRsaBcmathProvider::get_e

static function get_e($m)
{
	$et = '257';
	if(bccomp(self::GCD($et, $m), '1') != 0)
	{
		$et = '5';
		$c = '2';

		while(bccomp(self::GCD($et, $m), '1') != 0)
		{
			$et = bcadd($et, $c);
			if($c == '2')
					$c = '4';
			else
				$c = '2';
		}
	}

	return $et;
}