“…Recent advancements in decentralized data transactions via Blockchain [5], [11], IoT [12], MEC and Fog Computing [2], [7], [30] and 5G device-to-device (D2D) communication capability [27] will allow secure sharing economy services wherein any number of entities within a mass crowd, such as in a smart city, can perform a multiparty transaction in a decentralized manner [6], [7], [24], [25]. For example, recent medical equipment, such as CT Scan machine, has embedded IoT devices that enable data processing locally and upload the results to Blockchain and off-chain nodes running at the nearby edge [3], [7], [9], [22], [24], [28], [31]. Two parties can securely perform any online activity or financial or business transaction [3], [13], [26], [37].…”