ParagonIE\Halite\KeyFactory::loadKeyFile PHP Method

    protected static function loadKeyFile(string $filePath) : HiddenString
    {
        $fileData = \file_get_contents($filePath);
        if ($fileData === false) {
            throw new Alerts\CannotPerformOperation('Cannot load key from file: ' . $filePath);
        }
        $data = \Sodium\hex2bin($fileData);
        \Sodium\memzero($fileData);
        return new HiddenString(self::getKeyDataFromString($data));
    }