To cut to the chase, keeping your phone in a high-quality Faraday bag will conceal your location. This stops the State from tracking your every move, which can be really important in some situations. We recommend this one right here. You can support CLDC’s work by buying one from us, and it makes a great gift! However, a common misuse of Faraday bags is to try to stop your phone from eavesdropping on your in-person conversations.

This will not work. A Faraday bag isn’t designed to block sound, only to block cell phone, WiFi, and other electromagnetic signals. Let’s say your phone has been hacked and is now controlled by an adversary. It is now being used to record any conversations within range of its microphones (called “hot mic’ing”). All a Faraday bag can do in this case is prevent recordings from being transmitted in real time. Your hot mic’ed phone could still be recording. It would just need to wait until you’re back on a cellular or WiFi network to then send the recording to your adversary.

To defend against a hot-mic’ed phone (extremely unlikely for most activists) you need a soundproof box. We couldn’t actually find a totally soundproof box (cell phone microphones are dang sensitive), but here’s what you can do: Put your phone inside a waterproof (foam-lined) case and set your phone to play some obscure music or white noise loudly enough so you can faintly hear it from outside the case.  This should work pretty well in a closet, too.


Encryption makes it pretty safe to organize online. Nothing involving computers can ever be 100% safe, but activists make themselves, their organizations, and their movements much, much safer with every encrypted conversation and shared document. Ideally, we encrypt everything, and easy-to-pick up tools like Keybase, Cryptpad, Signal, and Wire make this possible, sacrificing only a few of the shinier features of the common (and totally untrustworthy) corporate alternatives. These and other end-to-end encrypted apps and platforms make mass surveillance pretty much useless. Encrypting your non-sensitive communications, including your memes, jokes, and gossip is worthwhile, since access to a group’s shared culture makes light work of sowing divisions or putting infiltrators in place.

But what if the State chooses to target a specific activist or group, and take over their devices and read their encrypted messages? The tools to do so are costly—in excess of $1 million to remotely break into an up-to-date smartphone. This is only partly what we mean when we say that encryption raises the costs of surveillance. After all, money isn’t a limiting factor for governments and private security agencies serving corporations with deep pockets. The main cost is political, and comes with the risk of discovery. Compromising activists’ devices is the only sure way of getting someone’s encrypted messages and files, but this requires an active attack that can be discovered. This is unlike passive mass-surveillance methods, which happen out in cyberspace (not on activists’ devices) and are mostly undetectable. The political risk is to the State is that if they’re caught using hardcore spy tools against peaceful eco defenders or human (or non-human animal) rights defenders, this further discredits the State and undermines its legitimacy. This might actually help your campaign by increasing public sympathy and drawing attention to your group and your cause.


What if you or your friends are believed to be high-value targets (You’re so close to stopping that oil pipeline or export terminal for good!), and you already believe in-person meetings are the only safe option. The State decides to risk discovery and deploys malware to take control of the phone of one or more people in your group. Any compromised phone can be used to record (and transmit) conversations within range of the phone’s microphone, even when it appears to be turned off. Taking the battery out isn’t really an option for most modern, totally sealed phones. Here’s where soundproofing comes into play: Playing loud (obscure) music or (random) white noise while the phone is in the case means that the microphone’s sensitivity (gain) is going to be turned way down. In a very quiet environment (a distant closet or mostly-soundproof box), a modern cell phone mic will be straining to listen (gain turned all the way up). The final thing to think about is that random noise is best; it’s actually not too hard to cancel out a well-known song from the background conversation (using classic audio-editing apps like Audacity or seriously cutting-edge machine learning DJ-sampling tools like spleeter. Flooding the mic with sound (gain turned all the way down) should prevent any mic from even detecting your words in the first place.

Activists often consider conversations (like detailed direct-action discussions) to require the highest-possible level of security, and for these it’s common practice to keep some conversations in-person-only. You can just put your phones in another room, but there can be good security reasons why you’d rather keep your phone under your physical control. (It’s way easier to mess with a device if you can get your hands on it, and maybe you’re meeting with people you don’t 100% trust).

Finally, About Private In-Person Meetings

The safest option is for everyone to just leave phones at home.  But it’s understandable that not having even emergency access to a phone could be a safety issue for vulnerable folks, or otherwise could just be too much of a hassle.

It’s best for folks to put their phones into a Faraday bag before they head out to the meeting, and not to take them out until after they’ve gone home or reached another destination. Even better, give phones to roommates to take out with them to the bar you frequent together, and meet up with them afterward (turning cell phones off for long periods is pretty unusual, unless you and friends are often using a Faraday bag day-to-day). The worst idea is to wait to get to the meeting location to put phones into Faraday bags.  This means all of your phones go off the network at the same place, all at the same time.  Anyone watching (or looking at records of) the cell networks can easily guess that you’re all having a secret meeting together.

Stay safe out there!