We asked Harley, a Proton privacy expert on our team, to walk through the physical gadgets she and her colleagues use to protect themselves when a password alone isn’t enough.
None of these replace good digital hygiene, but they cover the gap where the digital world meets the physical one: a stolen laptop, a fake cell tower, a shoulder surfer on the train.
BusKill: a kill switch for laptop theft
Picture working in a café. You look away for a second and someone grabs your laptop and runs. BusKill(nieuw venster) is a magnetic cable built for exactly that moment. If it disconnects unexpectedly, it can lock your screen, suspend the machine, shut it down entirely, or even wipe the drive, depending on how you configure it. It’s a simple mechanism for a very physical threat, and one you’ll hope to never need.
IMSI catcher detectors: watching for fake cell towers
Phones constantly search for nearby cell towers, which is normally fine. The problem is IMSI catchers: fake towers that trick phones into connecting, sometimes exposing identifying information in the process. Law enforcement has used them to log who attended a protest. An IMSI catcher detector like the open-source AIMSICD(nieuw venster) monitors the cellular environment for signs something is off. It can’t prove a fake tower is present, but it can flag suspicious behavior.
Faraday pouches: going wireless-dark on demand
A Faraday pouch(nieuw venster) looks like a lunch bag but blocks electromagnetic signals entirely, cutting off cellular, Wi-Fi, and Bluetooth. A phone inside one can’t be tracked, reached, or connected to anything. Some Proton employees use one while traveling or whenever they want certainty that a device is genuinely offline, not just in airplane mode.
Security keys: a physical second factor
A password alone protects nothing once it’s phished. A hardware security key like a YubiKey(nieuw venster) or Nitrokey(nieuw venster) adds a physical requirement on top of it, so a stolen password isn’t enough to get in. Many keys also store encryption keys and perform cryptographic operations on-device, keeping sensitive material off a laptop that might already be compromised. Buy two: one to use, one to store safely as a backup, since losing your only key is its own kind of lockout.
Privacy screen protectors: blocking the oldest attack there is
A privacy screen protector(nieuw venster) uses thousands of microscopic vertical filters, small enough to be invisible, that let light through straight on and block it from the side. The screen reads clearly to you and as a blank surface to the person next to you. It’s built to stop the simplest attack on the list: someone reading over your shoulder on a train, in an airport, or in an open office.
USB data blockers: charging without the data risk
Public USB ports carry both power and data, which is exactly the problem when your battery is at 2% in an airport. A USB data blocker(nieuw venster), sometimes called a USB condom, physically blocks the data pins while letting power through. Your phone charges. Nothing else happens.
Cash: the original privacy tool
Every card payment leaves a record of where you were, when, and how much you spent. Cash doesn’t. It’s a reminder that privacy isn’t only a digital concern. The same instinct that leads us to encrypt an inbox should extend to the physical trail we leave behind.
