Freeloader's guide through the google galaxy

Abstract

One of the largest impediments to pervasive sensing is ensuring equally pervasive network access. While we can create wireless sensors that last for years without human intervention, the network infrastructure to support their deployment requires planning, power, and maintenance. The potential for a crowd-based solution to this problem is ripe - -ever pervasive smart phones have the hardware and connectivity to serve as ubiquitous mobile gateways - -however the fragmentation of low power wireless protocols combined with the lack of incentive for users to sacrifice their own resources transporting others' data has made this approach untenable. Through an "off label'' use of Google's Physical Web and Nearby Notifications, it was possible to ignore these problems and exploit nearly the entire global population of Android phones to slowly transport sensor data to an arbitrary web server. This mechanism was enabled by default and transparent to the phone's user. On one hand, it served as an exciting opportunity to explore infrastructure-free wireless networking. In a one week deployment of five devices transmitting at 1\,Hz, we were able to successfully transport 326\,kB of data with an average data rate of 0.1 - 2.6\,bps. This is slow, but sufficient for many applications such as environmental monitoring and sensor status reporting. On the other hand, a mobile operating system probably should not have enabled exfiltration of arbitrary data without a user's knowledge or consent. While Nearby Notifications has now been decommissioned, we examine security policy requirements for future systems that interact with nearby devices, and we envision a similar, intentional mechanism to allow data hitchhiking for the Internet of Things.