The PET Paradox: How Amazon Instrumentalises PETs in Sidewalk to Entrench Its Infrastructural Power

Imagine the internet as a giant, bustling city. In this city, there are special tools called Privacy Enhancing Technologies (PETs). Think of these like invisible cloaks or locked safes. Their job is to hide your secrets, making sure that when you send a message or share data, no one else can peek inside. The big dream of these tools is to stop giant companies from having too much power over regular people, creating a fairer balance where you control your own information.

But here's the twist: what if the person handing you the cloak is actually the same giant company you're trying to protect yourself from? And what if, while they are zipping up your cloak, they are secretly using the fabric to build a giant, invisible bridge that connects everyone's house to their own private fortress? This is the puzzle scientists are starting to notice. They are asking: Can these privacy tools actually end up making the big companies even stronger, while making us feel safe? This paper dives into that exact question, looking at a real-world example to see if the "invisible cloak" is actually a trap.

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The Great Sidewalk Swap: How Amazon Built a Secret Highway

This paper investigates a real-life experiment by Amazon called Sidewalk. To understand what's happening, imagine your home is a house with a front door (your Wi-Fi router). Usually, only people inside your house can use that door. But Amazon came along with a clever idea: they asked millions of people to leave their front doors slightly open, just a crack, so their neighbors could walk through to get to their own destinations.

In the real world, Amazon did this by sending a software update to millions of Echo (smart speakers) and Ring (smart doorbell) devices. Suddenly, these devices became "gateways." They shared a tiny bit of their owners' internet bandwidth with other devices nearby. It sounds like a nice community project, like neighbors sharing a garden hose to water each other's plants. Amazon promised that this would help people find lost pets or keep smart devices connected even when they wandered far from home.

The "Invisible Cloak" Trick

To make people comfortable with this idea, Amazon used those Privacy Enhancing Technologies (PETs) we mentioned earlier. They put up a "Privacy Shield" (encryption and obfuscation). They told users, "Don't worry! We are hiding the data. No one can see what your neighbor is doing, and we can't see what your device is sending."

The paper argues that this is where the magic trick happens. By using these privacy tools, Amazon convinced people to flip a switch and turn their personal devices into part of a massive, crowdsourced network. But once the switch was flipped, something surprising occurred.

The paper finds that Sidewalk isn't just a simple "road" for data. It's actually a software production environment for IoT manufacturers.

Here is the analogy: Imagine Amazon built a giant, invisible highway that stretches across 90% of the United States. They didn't build the road themselves; they convinced millions of homeowners to pave a tiny strip of their own driveways to connect to it. Now, Amazon owns the highway. But the real trick is who else is using it.

Other companies (like makers of smart locks, air quality sensors, or pet trackers) want to send their devices onto this highway. Amazon says, "Sure, you can use our highway, but you have to follow our rules."

The Catch: You Have to Build Your Car My Way

This is where the "Paradox" kicks in. The paper shows that to use Amazon's highway, other manufacturers have to completely change how they build their products. It's not just about plugging in a cable; they have to:

1. Change their hardware: They must use specific computer chips approved by Amazon.
2. Change their software: They have to use Amazon's specific operating system (FreeRTOS) and encryption keys.
3. Change their factory: They have to set up special security machines in their factories just to "key" the devices with Amazon's secrets before they even leave the building.
4. Route their data: All the data from these devices must first go through Amazon's cloud (AWS). While they can eventually move that data to other servers via APIs, the initial connection and processing are locked into Amazon's ecosystem.

The authors call this turning other companies' devices into "accessories" of Amazon's cloud. It's like if you wanted to drive a car, but you had to build the engine, the tires, and the steering wheel exactly how Ford tells you, and you had to drive on a road owned by Ford, and you had to pay Ford to park your car in their garage.

But there's a hidden cost for these manufacturers. While the "cloak" hides data from neighbors, it doesn't hide the traffic from Amazon. In fact, the paper reveals that by connecting to Sidewalk, manufacturers are forced to send a stream of business-sensitive information directly to Amazon. Amazon can see exactly how many devices are being used, where they are, how much battery they consume, and how often they are triggered. This gives Amazon a crystal-clear view of the manufacturers' market demand and operational secrets. The paper notes that while some manufacturers hope Amazon won't use this data to copy their products, others feel resigned, knowing Amazon has a history of using third-party seller data to launch competing products. The "privacy shield" protects the user's data from the neighbor, but it leaves the manufacturer's business secrets wide open to the giant running the highway.

The Two-Faced Paradox

The paper calls this the PET Paradox, and it has two sides:

Side 1: The Privacy Promise vs. The Surveillance Reality
Amazon used privacy tools to convince you to share your internet. They said, "We are protecting your privacy!" But in doing so, they created a new network where they can see everything about how other companies' devices are working. They know when a sensor is triggered, how much battery it uses, and where it is. The "privacy cloak" hid the details from the neighbors, but it didn't hide the traffic from Amazon. In fact, it made the traffic flow more easily to Amazon's servers, exposing manufacturers' confidential data in the process.

Side 2: The Control Trap
The second side is about power. By forcing other companies to change their factories, software, and hardware to fit Amazon's rules, Amazon has locked them in. Once a company starts making devices for Sidewalk, it's incredibly hard to stop. They are now dependent on Amazon's rules, Amazon's cloud, and Amazon's security keys. The paper suggests that Amazon isn't just selling a service; they are taking over the production line of other companies.

What the Authors Found

The researchers didn't just guess this; they talked to eight different companies that actually use Sidewalk. They found that while these companies see some benefits (like easier updates for their devices), they feel a bit trapped. One company described it as "playing ball" with a giant. They know Amazon holds the power, but they feel they have to play along to stay in the game, even if it means handing over their business data and changing their production lines.

The paper concludes that Amazon used these privacy tools not just to protect you, but to entrench (make permanent and unshakeable) their own power. They turned your personal Echo speaker into a piece of their massive infrastructure, and they forced other companies to build their products to fit Amazon's mold, all while gaining a deep, confidential look into those companies' businesses.

The Big Takeaway

The paper warns us that we need to look deeper than just "Is my data encrypted?" We also need to ask: "Who owns the road my data is traveling on?" and "Who is building the car?"

The authors suggest that while privacy tools are great, we need to be careful when a single giant company controls both the tools and the infrastructure. If they use "privacy" as a way to get us to hand over our devices and our neighbors' devices to build their own private empire, then the tools might be doing the exact opposite of what they promised. Instead of balancing the power, they might be stacking it all on one side of the scale.

So, the next time you hear about a new "privacy-friendly" feature that asks you to share your internet or change your settings, remember the story of the invisible cloak. It might be hiding the neighbors, but it could be building a highway straight to the giant's fortress, while also handing the giant a detailed map of your neighbor's business.