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An Internet of Vehicles That's Both Connected and Private

Cooperative route planning and anonymity don't have to be mutually exclusive.
​Image: Mark Woodbury/Flickr

​Our information lives operate with astounding levels of organization. My hard-drives and inboxes might be chaotic messes ("chaotic" is being kind), but the technology that allows such chaos to exist in the first place is a marvel of efficiency and algorithmic correctness. Plugging an entire planet into this thing the internet requires nothing less.

For an indirect demonstration of this organization, look only to its polar opposite: automobile traffic. It's an ad hoc realm of pure inefficiency, where otherwise intelligent humans drive several thousands of pounds of metal into waiting gridlock and the indifferent, unsafe roadway grids beyond—on a daily basis. The internet of vehicles (IoV) aims to fix all of that, plugging vehicles into a global grid where they can be coordinated into vastly more efficient, safe schemes of cooperative route-planning.

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This seems inevitable, but it also would seem to have implications for privacy. The IoV needs to know your every move, present and future, to operate correctly. Is this just a necessary cost of increasing organization? ​Maybe not, argue a trio of computer scientists from Germany's Karlsruhe Institute of Technology. Without costing the system any utility or efficiency, it should be possible to offer string privacy guarantees.

The KIT researchers, led by network theorist Michael Florian, implement their internet of vehicle in terms of cooperative route planning. The basic idea is that, "all vehicles on the road publish their intended route and consider the published routes of others." The system then crunches all of this data and offers drivers better ways to get around. Imagine Google Maps traffic highlighter tool but predictive rather than just reactive and with a much higher resolution (individual trips even).

The problem, as defined by the KIT researchers, can be summarized like this: "In a completely anonymous system of peers, the promises of other participants cannot be fully trusted, which leads to a degraded system utility. On the other hand, user anonymity and unlinkability of user actions is highly desirable from a privacy standpoint." With help from a cryptographic construct known as promise coins, these two perspectives might not be quite as conflicting as it might seem.

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Promise coins are related to the concept of electronic cash, in which digital bills are issued using "blind signatures" that prevent the bills from being linked to the user later on. In terms of our internet of vehicles, users would be issued a set of promise coins from some central authority. The users then use these coins to make anonymous "promises" about their intended route, in effect paying the central authority one coin for every route published. In exchange, the user gets a promise token, and once they've completed their route as published, they swap that token for the original coin.

Paying that promise coin might give the user some extra benefits too, like toll or gas discounts. Similarly, we can imagine entire roadways or bridges closed off to users not following published route promises, which might then be viewed as reservations.

The larger principle, however, is this: users that don't fulfill their route promises will eventually run out of coins, shutting them out of the system and its benefits. So: anonymity in this system is no longer a free pass to skip the rules. No more traffic updates, limited-access shortcuts, free tolls, etc. Just old-school anarchy.

This system then guarantees three crucial properties. "Assuming the honesty of the service operator and the integrity of the entities under his control, malicious users cannot effectively abuse the cooperative route planning system for altering traffic flow," Florian and his team write. "Individual users participate in the system in an anonymous fashion, with no user actions or published routing information being linkable to them. Individual routes, which can potentially be linked back to user identities, are not easily reconstructible by the service operator." Everything is satisfied.

It's an interesting contrast to what many of us might consider to be truly smart transportation: public transportation. Here we have anonymity in public—faces in a crowded subway or bus, armed with a disposable transit pass. It remains a highly efficient (in total), safe way of getting from place to place, with no promises required.