src/Mcrypt/Mcrypt.php
protected function generateIV()
    {
        $sizeIV = $this->getSizeIV();

        if ($sizeIV === 0) {
            return $this;
        }

        $this->setIV(mcrypt_create_iv($sizeIV, MCRYPT_RAND));

        return $this;
    }
protected function generateIV()
    {
        $sizeIV = $this->getSizeIV();

        if ($sizeIV === 0) {
            return $this;
        }

        $this->setIV(mcrypt_create_iv($sizeIV, MCRYPT_RAND));

        return $this;
    }
Generate random IV & set it as property

@return self