Brain-Computer Interfaces: Can Your Brain Be Hacked?

There’s a moment in every sci-fi film where someone jacks a cable into the back of their skull and instantly downloads kung-fu. We laugh at it. We call it fiction. But right now, a former HR director named Pat Bennett living with ALS is generating sentences on a screen at 62 words per minute using only her thoughts. No cable. No hands. Just neurons and a cluster of electrodes embedded in her brain.

That’s not a movie. That’s a 2023 paper in Springer Nature( a German-British academic publishing company). And it raises a question nobody in the press release bothered to ask: her brain signals were being transmitted wirelessly, processed by external software, and stored on servers. So what happens when the most intimate data that exists of your actual neural activity becomes just another thing that can be breached?

We spent decades arguing about whether your phone was listening to you. We never thought to ask what happens when the device is inside your skull.

What a BCI Actually Does

A Brain-Computer Interface reads your brain's electrical signals and translates them into something a machine can act on. Your neurons fire in patterns. The BCI captures those patterns, filters out noise, runs them through a machine learning model, and converts the output into a command: move a cursor, type a word, control a robotic arm.

There are two architectures, and the difference matters enormously, both for capability and for security.

Non-invasive BCIs use electrodes placed on your scalp. These are the EEG headsets you've seen in documentaries, increasingly on retail shelves. Easy to put on, easy to take off. The tradeoff here is signal clarity, you're reading brain activity through skin and bone, so the resolution is limited. Consumer devices from companies like Emotiv, Muse, and Neurosity work this way.

On the other hand, Invasive BCIs implant microelectrode arrays directly into brain tissue. Much higher fidelity. Much higher stakes. Neuralink’s device works this way. So does the system used in the BrainGate clinical trials that produced Pat Bennett’s results.

(Neuralink is a neurotechnology company founded by Elon Musk that develops implantable Brain-Computer Interface (BCIs) to connect human brains directly to computers.)

BrainGate implanted four microelectrode arrays in the region of Bennett's brain responsible for speech. Within 30 minutes of activation, in a separate trial published in the New England Journal of Medicine, the system demonstrated 99.6% accuracy on a 50-word vocabulary. Bennett's own results achieved 62 words per minute which is more than three times faster than any previous BCI that demonstrated a 9.1% word error rate on a 50-word vocabulary and 23.8% on a 125,000-word vocabulary. She used the system at home. Unsupervised. Via a wireless connection.

That last part is the part nobody talks about.

The Threat Landscape

The phrase “hacking a brain” sounds cinematic. Let’s be precise about what it actually means, because the reality is both more mundane and more alarming than the movies suggest.

Signal interception Most modern BCIs transmit data wirelessly because the alternative is a cable permanently protruding from someone's head, which creates its own obvious problems. Wireless transmission solves that. It also introduces a new one: anything broadcast over radio can, in principle, be received by anyone within range with the right equipment.

Neural signals are not like passwords. A stolen password reveals what you typed. Intercepted neural data can reveal things you didn't consciously express such as stress responses, emotional states, subconscious reactions to faces or images or words. A previously conducted study demonstrated that EEG data alone could be used to infer a user's PIN with meaningful accuracy. Another research group showed that neural signals recorded during passive viewing could be used to reconstruct, in rough form, what someone was looking at.

The data being transmitted isn't just "she wanted to type the letter A." In high-fidelity invasive systems, it's a continuous stream of electrical activity from inside the brain which is definitely far richer, and far more revealing, than anything the user explicitly intended to send.

Firmware and parameter tampering Any device that accepts over-the-air updates or remote configuration commands can, in principle, be told to do something its owner didn't authorise. This is not a theoretical concern; it's already happened with other implanted medical devices.

In 2012, security researcher Barnaby Jack demonstrated that pacemakers could be wirelessly commanded to deliver an 830-volt shock from fifty feet away from a potentially fatal attack requiring no physical access to the patient. The attack worked because the device trusted any command that arrived in the right format. It didn't verify who was sending it.

BCIs share this exact attack surface. A device that stimulates the motor cortex (a region in the frontal lobe of the brain, responsible for planning, controlling, and executing voluntary skeletal muscle movements) to help a paralysed patient move a limb is, functionally, a device that applies electrical signals to brain tissue. The security question of who gets to authorise those signals and how the device verifies that authorisation is not a minor implementation detail.

This makes over-the-air updates a particular concern. An unprotected update channel is an attack surface. A device that accepts remote updates can, if that channel isn't properly secured, accept them from anyone, not just the manufacturer. For most software, a malicious update is a serious nuisance. For an implanted neural device, it becomes a different league of threat.

(Over-the-air updates means delivering a software update wirelessly, without any physical connection. For example your phone does this when it downloads an iOS or Android update in the background. )

Data exfiltration at the platform level This is the attack vector that requires the least sophistication and carries the most scale. It doesn't require hacking the implanted device at all.

Neural data in most current BCI systems is offloaded to external servers, for processing, storage, model training. Those servers are subject to the same breaches as any other database. The difference is the nature of what's stored. A leaked email password is annoying. A leaked database of neural recordings is something you cannot fix. You can't reset your brain. You can't issue yourself a new neural profile. The data is permanently identifying, permanently sensitive, and permanently yours in the sense that it can never stop describing you, even after it's out of your hands.

The Privacy Problem Is Actually Worse

Here’s something worth sitting with: most of the neural data risk doesn’t come from sophisticated cyberattacks. It comes from completely legal data practices.

Emotiv, one of the world's largest consumer EEG manufacturers, allows sharing of anonymised neural data with third parties for research and commercial purposes. This isn't a breach. It's in terms of service. A Neurorights Foundation survey of 30 direct-to-consumer neurotechnology companies found that clicking "I agree" on 29 of them would grant the company the right to sell that neural data to third parties. The users generating those neural profiles had no meaningful visibility into how the data would be used, by whom, or for how long.

Think about what that actually means. You buy a consumer EEG headset to meditate, or to study, or to experiment. You click through the setup screens. You have now, legally, handed a company the right to sell recordings of your brain activity, which may contain traces of your emotional states, your cognitive responses, your subconscious reactions to the content you consumed while wearing the device to anyone willing to pay for it.

The legal weight of this became sharply visible in 2023, when Chile's Supreme Court ordered Emotiv to delete the brain data it had collected on a former senator. The court found that retaining anonymised neural data for research purposes, without specific prior consent, violated his constitutional rights. That case was possible because Chile had done something no other country on earth had done: it amended its constitution to enshrine the right to mental privacy and cognitive liberty directly in its founding law. The senator had a right to invoke. Most people don't.

Major data protection frameworks, including GDPR in Europe, have no specific provisions for neural data. In the United States, Colorado and Minnesota have begun developing targeted neurotechnology legislation. Federal protections do not yet exist. The gap between what the technology can do and what the law protects against is wide, and it is being filled, right now, by individual companies making individual choices about what to do with data that has never existed before in human history.

What Secure Neurotechnology Looks Like

The security community has been here before with pacemakers, with insulin pumps, with every connected medical device that shipped convenience before it shipped caution. The technical lessons from those fights aren't complicated. They're just being ignored again.

Encryption, end-to-end. Neural data should be encrypted both in transit and at rest. Manufacturers will tell you implanted devices don't have the power budget for heavy cryptography. That's an engineering problem, in that a solvable one, not an acceptable reason to ship unencrypted hardware into someone's brain.

Proper authentication for every connection. The attack that let Barnaby Jack command a pacemaker to fire from fifty feet away worked because the device accepted any command that arrived in the right format. No verification of who was sending it. Every wireless connection to a BCI should require real mutual authentication not "the device responded, so we trust it."

Secured over-the-air updates. Firmware updates need to exist, because the alternative which would be requiring surgical intervention every time a security patch is needed is clearly untenable. But they need to be cryptographically signed and verified, so that a device can confirm it's receiving a legitimate update from a legitimate source rather than instructions from an attacker who's learned the update protocol.

A real off switch. This one gets the least attention. Users should be able to disable the wireless radio entirely. Not airplane-mode-but-still-broadcasting off. Actually TURN off. A device that is permanently broadcasting neural data is a device that is permanently exposed. The user should have the ability to make that exposure stop.

And underlying all of these: security needs to be designed in from the beginning, not bolted on after the product ships. The IoT industry made the convenience-first choice a decade and a half ago with smart home devices, and we are still cleaning up the consequences. The difference is that a compromised thermostat sends your heating schedule to a stranger. A compromised BCI has electrodes in your motor cortex.

The Window Is Closing

Maybe you're not planning to get a brain implant. Here's the scale of what's already happening, whether you are or not.

On March 30, 2025, Precision Neuroscience received FDA 510(k) clearance for its Layer 7 Cortical Interface, the first full regulatory clearance granted to a company developing a next-generation wireless BCI. Neuralink has implanted devices in multiple human patients. Emotiv, Muse, and Neurosity EEG headsets are on retail shelves. The distance between "laboratory prototype" and "consumer product" is compressing faster than anyone predicted five years ago.

(Precision Neuroscience is a neurotechnology company developing a minimally invasive brain-computer interface (BCI) designed to help patients with paralysis control digital devices using only their thoughts.)

The security and regulatory infrastructure is not keeping pace. The devices are moving faster than the rules, faster than the security research, faster than the legal frameworks that would tell a company what it is and isn't allowed to do with the data those devices generate. Someone has to close that gap.

The skills that make someone good at CTF reading systems for weaknesses, thinking like an attacker, finding the edge case nobody planned for are exactly the skills this field is missing. Neurotechnology has researchers and neuroscientists. It doesn't have enough people asking what breaks.And here we have a target that actually matters.

The skills that make someone good at security research, reading systems for weaknesses, thinking like an attacker, finding the edge case nobody planned for are precisely the skills this field is missing. Neurotechnology has neuroscientists and electrode engineers and machine learning researchers. It does not have enough people whose job is to ask: what breaks? What gets abused? What does this look like from the other side?

Why This Matters More Than It Seems

There's a version of this story where BCIs are simply the next generation of consumer technology — a more intimate interface, a cleverer device, with the same security challenges and the same eventual solutions as everything before it.

There's another version where they're categorically different.

Every piece of consumer technology before this has captured what you do: what you search, what you buy, where you go, what you say. BCIs capture what YOU are, the electrical signatures of thought and emotion and reaction that exist below the level of deliberate expression. Data that you didn't choose to generate. Data that reveals things about you that you might not know about yourself.

The engineers building the next generation of these devices will make decisions, about encryption, about data retention, about what gets transmitted and what gets stored and what gets sold which will determine whether neural interfaces become tools of human dignity or the foundation of a surveillance infrastructure that nobody consciously consented to. Those engineers are, in many cases, students right now. Some of them are security researchers who haven't yet looked at this space.

It is worth looking at this space. Before someone else makes the decisions for you. Before the terms of service have already been agreed to. Before the data that cannot be reset has already left the building.

The window is open. It won't stay open.