Kadupul: Livin' on the Edge with Virtual Currencies and Time-Locked Puzzles

Abstract

Devices connected to the Internet today have a wide range of local communication channels available, such as wireless Wifi, Bluetooth or NFC, as well as wired backhaul. In densely populated areas it is possible to create heterogeneous, multihop communication paths using a combination of these technologies, and often transmit data with lower latency than via a wired Internet connection. However, the potential for sharing meshed wireless radios in this way has never been realised due to the lack of economic incentives to do so on the part of individual nodes. In this paper, we explore how virtual currencies might be used to provide an end-to-end incentive scheme to convince forwarding nodes that it is profitable to send messages on via the lowest latency mechanism available. Clients inject a small amount of money to transmit a message, and forwarding engines compete to solve a time-locked puzzle that can be claimed by the node that delivers the result in the lowest latency. Our approach naturally extends congestion control techniques to a surge pricing model when available bandwidth is low and does not require latency measurements.