Bitpay\PublicKey::getSin PHP Method

    public function getSin()
    {
        if (empty($this->hex)) {
            $this->generate();
        }
        if (null === $this->sin) {
            $this->sin = new SinKey();
            $this->sin->setPublicKey($this);
            $this->sin->generate();
        }
        return $this->sin;
    }