Fog-based file sharing for secure and efficient file management in personal area network with heterogeneous wearable devices

In a personal area network (PAN) with wearable devices, the security of a file stored is an important concern. Secret sharing has received considerable attention for handling security, as it guarantees confidentiality and integrity even when some devices, whose count when taken together less than the minimum threshold, are compromised, lost, or stolen. However, because traditional secret sharing has tremendous computational overhead and requires a large storage space, it is not appropriate for battery-powered wearable devices. To overcome this limitation, combinatorial-based file sharing is proposed. However, this incurs another efficiency problem, as preparation of file storage and retrieval involves computational costs. Additionally, this file sharing has been designed without considering an environment with heterogeneous wearable devices. To overcome the aforementioned problems, we first propose a new fog network model that delegates the calculation for the preparation of file storage and retrieval to a fog node, such as a smartphone or tablet PC. A fog node has relatively faster operational ability and larger battery capacity, and hence the resources of the devices in the PAN can be managed efficiently. Additionally, we propose a new algorithm that generates file shares by considering the heterogeneous characteristics of wearable devices. In particular, we consider the factors of storage capacity and network speed to determine the sizes of the file shares. We demonstrate that our proposed model manages the file stored efficiently, using mathematical analysis and simulations.