public function getCode($secret, $time = null)
{
$period = $this->getPeriod($time);
$secret = $this->base32->decode($secret);
$time = pack("N", $period);
$time = str_pad($time, 8, chr(0), STR_PAD_LEFT);
$hash = hash_hmac('sha1', $time, $secret, true);
$offset = ord(substr($hash, -1));
$offset = $offset & 0xf;
$truncatedHash = $this->hashToInt($hash, $offset) & 0x7fffffff;
$pinValue = str_pad($truncatedHash % $this->pinModulo, $this->passCodeLength, "0", STR_PAD_LEFT);
return $pinValue;
} public function testCheckCode()
{
$secret = '4FDAGLLSP6BIVU5H';
$time = 1375000339;
$code = $this->totp->getCode($secret, $time);
$codePrev = $this->totp->getCode($secret, $time - 30);
$codeNext = $this->totp->getCode($secret, $time + 30);
$this->assertTrue($this->totp->checkCode($secret, $code, $time));
$this->assertTrue($this->totp->checkCode($secret, $codePrev, $time));
$this->assertTrue($this->totp->checkCode($secret, $codeNext, $time));
}