The roadside is becoming a listening post, and your devices keep volunteering clues.<\/h5>\n\n\n\n![\"Blurred](\"https:\/\/media.reclaimthenet.org\/images\/2026\/10\/x6KGfK1NL5yT.jpg\")
<\/figure>\n\n\n\nBy Ken Macon<\/p>\n\n\n\n
On a seemingly ordinary road outside of Washington, DC, there are poles carrying gear that, according to its maker, logs the radio signals coming off phones, earbuds, and watches in passing cars, and ties this information to the car\u2019s license plate.<\/p>\n\n\n\n
In a post titled, \u201cThinking Critically About SignalTrace<\/u><\/a>\u201d \u2013 that was first published on August 2, 2026, and updated on September 18 \u2013 Ryan O\u2019Horo, who writes a blog on security, said he found four installations in Oxon Hill, Maryland, near National Harbor, on Oxon Hill Road and National Harbor Blvd, and that they are operated by the Prince George\u2019s County Police Department.<\/p>\n\n\n\nO\u2019Horo also found that \u201ca few hundred feet north, a Flock Safety ALPR camera<\/u><\/a> is installed.\u201d (Flock Safety is a company that makes automatic license plate readers, or ALPRs<\/u><\/a>.)<\/p>\n\n\n\nO\u2019Horo found two more installations, in Solomons and Dunkirk in Calvert County, Maryland, which are served by the Calvert County Sheriff\u2019s Department. He also published what he said was an invoice from June 2023 showing the sheriff\u2019s office bought two SignalTrace devices.<\/p>\n\n\n\n
O\u2019Horo noted that the antennas are located in a way that allows them to pick up signals from devices carried by pedestrians, not just those in vehicles.<\/p>\n\n\n\n
However, Reclaim The Net has not been able to confirm that the devices are actually in use, and that they are SignalTrace models.<\/p>\n\n\n\n
What the devices do is not something that those driving past them would know.<\/p>\n\n\n\n
The product page of SignalTrace, a surveillance tool made by Italy\u2019s Leonardo and sold to police in the US, has undergone changes in recent months \u2013 but the most important thing about it, its purpose, has remained the same.<\/p>\n\n\n\n![\"A](\"https:\/\/media.reclaimthenet.org\/images\/2026\/10\/5gmIglaTa1iX.jpg\")
<\/figure>\n\n\n\nThe product page, as it stood in June 2026, was very clear and direct: \u201cIdentify Suspects by the Electronic Devices They Use.\u201d<\/p>\n\n\n\n
At the same time, it was also clear that the product was not about the car itself, but the people in it \u2013 the pitch was about finding out who they are, by identifying their devices.<\/p>\n\n\n\n
In June, the page said the product was \u201cdesigned to help law enforcement identify people of interest by the signals emitted from their electronic devices they travel with, such as fitness trackers, smartwatches, RFID tags, and local signals from their mobile phones.\u201d<\/p>\n\n\n\n
When the reports first appeared in June<\/u><\/a>, no police department had been confirmed to have bought the product, but by late July, the \u201csuspects\u201d were gone from the product\u2019s page, and \u201cleads\u201d were in. And while the page still explains that the system can pinpoint a device by the unique signals it emits, the example given has been tweaked to remove the license plate, that was present in the June version.<\/p>\n\n\n\nOn August 4, 2026, Leonardo announced the new name<\/u><\/a>. The company said: \u201cSignalTrace does not identify individuals, access communications or retrieve information stored on personal devices.\u201d<\/p>\n\n\n\nThe New York City Police Department (NYPD) is preparing to spend three-quarters of a million dollars on a cell-site simulator<\/u><\/a> \u2013 a fake cell tower that vacuums up phone data of everyone in its vicinity.<\/p>\n\n\n\nThe contract with an Israeli company Cognyte is worth $750,500 and will last for three years, the New York Daily News is reporting<\/u><\/a>.<\/p>\n\n\n\nThe New York Civil Liberties Union (NYCLU) says this is \u201chighly intrusive\u201d and \u201cdragnet surveillance,\u201d and the new tech \u201cgoes even further by incorporating undisclosed AI capabilities that analyze people\u2019s behaviors.\u201d<\/p>\n\n\n\n
The NYPD has a policy<\/u><\/a> that is supposed to regulate the use of cell-site simulators, and it says that a warrant is required, and that the technology will not be used to intercept content of communications.<\/p>\n\n\n\nAnother exception to the warrant rule is if there\u2019s an emergency \u2013 but then the police must obtain the warrant within 48 hours. And there\u2019s also the \u201cmissing or suicidal person\u201d exception, when a search warrant is not required at all.<\/p>\n\n\n\n
Your phone is a snitch, and it\u2019s a chatty one at that. While you are not using it, it keeps asking out loud for the networks it has known \u2013 and, in a real street, that \u201cloud\u201d announcement can leak passwords, names, and information about your holiday home.<\/p>\n\n\n\n
Phones, when not connected to a Wi-Fi network, keep looking for one to connect to, and they do this by sending out what\u2019s known as a probe request.<\/p>\n\n\n\n
The University of Hamburg\u2019s Johanna Ansohn McDougall and her colleagues<\/u><\/a> decided to see what exactly is happening in this process, and how much sensitive information is being leaked. They recorded the data sent out by phones in a busy street in a German city for an hour, three times.<\/p>\n\n\n\nThe team found that 23.2 percent of the probe requests contained the names of the networks, known as SSIDs.<\/p>\n\n\n\n
As the researchers note, \u201cusers (probably by accident) input a wealth of data into the SSID field and find passwords, e-mail addresses, names and holiday locations.\u201d<\/p>\n\n\n\n
What\u2019s more, \u201can attacker could follow the owner of a talkative device to their home and try out the password in their home network.\u201d<\/p>\n\n\n\n
Earbuds, watches, fitness bands and cars all broadcast short Bluetooth announcements all the time, so that phones can find them. And phones, in turn, rotate their Bluetooth addresses so that a listener sees a string of strangers rather than one device.<\/p>\n\n\n\n
In 2019, a team from Boston University<\/u><\/a> (Johannes Becker, David Li, David Starobinski) wrote: \u201cwe show that many state-of-the-art devices which are implementing such anonymization measures are vulnerable to passive tracking that extends well beyond their address randomization cycles.\u201d<\/p>\n\n\n\nThe team tested Fitbit watches and found that \u201cwhile the TxAdd flag indicates that the devices use random addresses, the addresses actually never change\u201d \u2013 and that \u201cthe smartwatch advertises approximately once every 7 seconds using this format.\u201d<\/p>\n\n\n\n
O\u2019Horo says that \u201cBluetooth devices particularly tend to reveal the model in the device name, so even when they use BLE\u2019s address randomization feature, you could know you\u2019ve captured information about Bose product, or an infotainment system installed in an Audi.\u201d<\/p>\n\n\n\n
Apple itself advises users<\/u><\/a>: \u201cYou can change the name of your iPhone, which is used by iCloud, AirDrop, Bluetooth\u00ae, your Personal Hotspot, and your computer.\u201d<\/p>\n\n\n\nIf you name your iPhone Fred’s iPhone \u2013 that\u2019s what it will be announcing to the world as its Bluetooth name, its hotspot name, and on AirDrop.<\/p>\n\n\n\n
When you switch off Wi-Fi and Bluetooth on your phone, they don\u2019t always stay switched off.<\/p>\n\n\n\n
On Android, there\u2019s a setting that most people never chose but is enabled by default and keeps scanning for networks and devices even after you think you turned the radios off.<\/p>\n\n\n\n
On iPhone, the Control Center\u2019s \u201cquick\u201d buttons<\/u><\/a> for Wi-Fi and Bluetooth don\u2019t actually switch them off, they just disconnect from the networks and devices they were connected to, but remain available for future connections, and the system will use them if it sees fit.<\/p>\n\n\n\nThen there\u2019s the cellular network. Your phone has to identify itself to it, and that\u2019s done by sending the subscriber number (IMSI) and device number (IMEI) to the network. The problem is that a fake cell tower will ask the same questions, and the phone will provide the same answers.<\/p>\n\n\n\n
This is why, as Google\u2019s Android security team has noted<\/u><\/a>, it\u2019s easy to \u201cpush\u201d a phone down to 2G, where the \u201cattackers abuse the well known lack of mutual authentication in 2G and force connections to be unencrypted.\u201d<\/p>\n\n\n\nIn other words, 2G is an open door that, if not closed, can be easily exploited. It\u2019s not a question of whether your carrier still uses 2G in your area or not, because \u201cusers are still vulnerable to this type of fraud as long as mobile devices support 2G, regardless of the status of 2G in their local carrier,\u201d the Android team warned.<\/p>\n\n\n\n
O\u2019Horo says that SignalTrace can likely only collect data from Wi-Fi, Bluetooth, and certain 915MHz RFID devices \u2013 but not from every device, and not every time, given that cars are moving and all.<\/p>\n\n\n\n
Newer phones do randomize their MAC addresses, and their signals are brief and \u201chopped\u201d across different channels, which means that a roadside sensor is only getting fragments of data. But randomization is not the solution to the problem of device tracking. In 2016, Mathy Vanhoef and colleagues published a paper<\/u><\/a> that showed that this method \u201cdoes not guarantee privacy.\u201d<\/p>\n\n\n\nThe end result is that it is the people using cheaper and older devices who are least protected from tracking, as O\u2019Horo noted: \u201cThis also creates an economic inequity. More modern and expensive devices defend against tracking better, including devices in more expensive vehicles.\u201d<\/p>\n\n\n\n
Many of the iPhone \u201cfixes\u201d to make the device less trackable cost absolutely nothing.<\/p>\n\n\n\n
For one thing, those \u201cconvenience\u201d buttons in the iPhone\u2019s Control Center don\u2019t actually turn off the device\u2019s radios. Settings does.<\/p>\n\n\n\n
If you want to turn off Wi-Fi and Bluetooth, don\u2019t do it from the Control Center \u2013 instead, go to Settings, then Wi-Fi, and turn it off there. The same goes for Bluetooth.<\/p>\n\n\n\n
If you\u2019re using iOS 18 or a later version, you can make the device rotate the Wi-Fi address it uses to connect to a network<\/u><\/a>. To do this, go to Settings, Wi-Fi, tap the More Info button next to the network you\u2019re connected to, then go to Private Wi-Fi Address, and turn it on. You can choose to have the address rotate every two weeks, or keep it fixed. Apple advises that a fixed address is used by default when joining a network that uses WPA2 or stronger security. The company also explains that if the device always uses the same address across all networks, observers can more easily identify it and track its activity and location.<\/p>\n\n\n\nIf you have any hidden networks saved, delete them, because the phone has to call out the name of a hidden network to find it.<\/p>\n\n\n\n
There are a few more things you can do in Settings to make your iPhone a little less trackable. One is to rename the device. You can do this by going to Settings, General, About, Name. Apple says the name is \u201cused by iCloud, AirDrop, Bluetooth\u00ae, your Personal Hotspot, and your computer.\u201d So renaming it to something not very descriptive of you or your device would be a good idea. This will also rename your hotspot.<\/p>\n\n\n\n
You can never truly \u201cturn off\u201d an iPhone \u2013 but there are trade-offs.<\/p>\n\n\n\n
Find My, which keeps an iPhone \u201cdiscoverable\u201d for up to 24 hours after it\u2019s been turned off, is useful if the phone is stolen \u2013 but it also means the phone is never really off.<\/p>\n\n\n\n
Apple has instructions on how to turn off Find My<\/u><\/a> on a device before switching it off, and you can also do it by tapping on the note that appears on the power-off screen.<\/p>\n\n\n\nThen there\u2019s Lockdown Mode, which is the only way to turn off 2G on an iPhone \u2013 but it\u2019s a heavy tool that should not be used lightly.<\/p>\n\n\n\n
Apple itself says that Lockdown Mode<\/u><\/a> is \u201can optional, extreme protection that\u2019s designed for the very few individuals who, because of who they are or what they do, might be personally targeted by some of the most sophisticated digital threats. Most people are never targeted by attacks of this nature.\u201d<\/p>\n\n\n\nThose who might be \u201cpersonally targeted by some of the most sophisticated digital threats\u201d would be reasonable candidates for using Lockdown Mode \u2013 that means journalists, activists, and anyone with a reason to believe they are a target. Not someone who simply wants to reduce their general exposure to tracking.<\/p>\n\n\n\n
For those who are, or might soon become a target, Lockdown Mode can be found here: Settings, Privacy & Security, Lockdown Mode.<\/p>\n\n\n\n
As for AirDrop, it should be kept on Contacts Only, and never set to \u201ceveryone.\u201d This can be done by opening the Control Center, touching and holding the top-left controls, tapping AirDrop, and choosing Contacts Only.<\/p>\n\n\n\n
Ultimately, the choice is yours.<\/p>\n\n\n\n
Your first job after setting up your new Android device is to undo a setting it switched on for you.<\/p>\n\n\n\n
We\u2019ll get to what that is in a moment, but first, some advice: go into Settings, Location, Location Services, and turn off both Wi-Fi scanning and Bluetooth scanning. On Android 11 and older, these are located directly under Settings, Location.<\/p>\n\n\n\n
You do this because these two are switched on by default, as a Google note from 2018 reveals<\/u><\/a>, and as confirmed by GrapheneOS, which is an Android distribution that ships with these settings off.<\/p>\n\n\n\nWhile you\u2019re there, turn off Improve Location Accuracy. Google itself said that \u201cWhen Location Accuracy is on, Google periodically collects information about sensors and wireless signals near you to contribute to crowdsourced wireless signal locations.\u201d<\/p>\n\n\n\n
Another thing to change is the device name that\u2019s broadcast by Wi-Fi and Bluetooth. Go to Settings, About phone, Device name, and change it from whatever it is to whatever you want it to be. The name of the hotspot is changed in a different place: Settings, Network & internet, Hotspot & tethering, Wi-Fi hotspot, Hotspot name.<\/p>\n\n\n\n
Next, make sure that the MAC address of your device is randomized. Android\u2019s own documentation says<\/u><\/a> that \u201cBy default, Android uses persistent randomization.\u201d But persistent means it doesn\u2019t actually change, ever. As the documentation also has it, \u201cThis MAC address remains the same until a factory reset.\u201d It doesn\u2019t even change if you forget a network and then re-add it.<\/p>\n\n\n\nIf you want your MAC address to actually change each time you connect to a network, you have to go to the developer options and enable \u201cWi-Fi non-persistent MAC randomization.\u201d<\/p>\n\n\n\n
The latest Android version, Android 16, brings several security and privacy features, but also one that is not immediately obvious: the 2G switch has been flipped.<\/p>\n\n\n\n
Instead of turning 2G off, as was the case in Android 12 to 15, now you turn 2G network protection on<\/u><\/a>.<\/p>\n\n\n\nThe new setting is in Settings, Network & internet, SIMs, 2G network protection.<\/p>\n\n\n\n
Not all phones running Android 16 will have this setting, however. Samsung phones, for example, don\u2019t have a separate 2G switch; on One UI 6.1.1 and later, it is part of Settings, Security and privacy, Auto Blocker, Maximum restrictions. Samsung also warns<\/u><\/a> that turning it on may interfere with calls, messages, and mobile data in areas where only 2G service is available.<\/p>\n\n\n\nAndroid 16 has also added a new section, Mobile network security, which can show notifications when the phone connects to an unencrypted network or is asked for its IMSI or IMEI. But the latter requires modem support, which, according to a 2025 report by the German site teltarif<\/u><\/a>, current Pixels lack.<\/p>\n\n\n\nThen there is the ability to find devices even when they are offline. This is the same trade-off that Apple\u2019s Find My iPhone has been making for years, and Google is not shy to admit it.<\/p>\n\n\n\n
\u201cBy default, your Android device stores encrypted recent locations with Google and participates in the Find Hub network,\u201d Google\u2019s documentation reads<\/u><\/a>.<\/p>\n\n\n\nYou can turn this off, but it is on by default.<\/p>\n\n\n\n
To do so, go to Settings, Google, All services, Find Hub, Find your offline devices. Then, you can choose from Off, Without network, With network in busy places only, and With network everywhere.<\/p>\n\n\n\n
For those willing to go the extra mile, there is GrapheneOS, a privacy and security-focused mobile operating system that is a hardened version of Android, and can run on Pixel phones.<\/p>\n\n\n\n
GrapheneOS gives a new random Wi-Fi address on every connection<\/u><\/a>: \u201cGrapheneOS supports per-connection MAC randomization and enables it by default.\u201d<\/p>\n\n\n\nIf you have a reliable LTE connection, GrapheneOS advises<\/u><\/a>, \u201cyou can reduce attack surface by disabling 2G, 3G and 5G connectivity in Settings > Network & internet > SIMs > SIM > Preferred network type.\u201d<\/p>\n\n\n\nYou might be able to switch your phone off, or put it in airplane mode, and if you can, you should \u2013 but what about all the other devices that are now attached to you and the car?<\/p>\n\n\n\n
You can unpair devices you no longer use, and switch off those you don\u2019t need at a particular time.<\/p>\n\n\n\n
What about the car itself?<\/p>\n\n\n\n
You can check its settings to see if its own Wi-Fi hotspot can be switched off, and if it can, do that \u2013 unless you absolutely need it, in which case at least make sure to change its name to something that doesn\u2019t reveal your identity.<\/p>\n\n\n\n
Then there are the tire sensors. They will keep shouting their ID, a fixed number, whatever you do.<\/p>\n\n\n\n
IMDEA Networks researchers and their colleagues said in a paper in 2026<\/u><\/a> that these sensors send out signals with a unique identifier that doesn\u2019t change over \u201cvery long periods of time.\u201d<\/p>\n\n\n\n\u201cBecause each sensor broadcasts a fixed unique ID, the same car can be recognized repeatedly without reading a license plate,\u201d the researchers said in a press release<\/u><\/a>.<\/p>\n\n\n\nYago Lizarribar, one of the authors, said that tire pressure monitoring system (TPMS) was \u201cdesigned for safety, not security.\u201d<\/p>\n\n\n\n
The only real off switch is a good Faraday pouch.<\/p>\n\n\n\n
Airplane mode is not an off switch \u2013 it\u2019s a button with a misleading name. Apple\u2019s support website says<\/u><\/a> that on an iPhone, \u201cthis turns off all radios except for Bluetooth.\u201d And even that statement is not entirely true, because, as Apple also notes, \u201cif the airline allows it, you can still use Wi-Fi and Bluetooth in Airplane Mode.\u201d<\/p>\n\n\n\nSo \u2013 a Faraday pouch it is. But not just any will do. In 2021, security researcher Matt Blaze tested several<\/u><\/a>, and the cheap ones, like mylar bags, didn\u2019t do well: \u201cIn no instance did any of my mylar\/ESD bags provide more than about 9 dB of attenuation.\u201d<\/p>\n\n\n\nBlaze also warned against a weak test of the pouch\u2019s effectiveness: \u201cA less useful test is to simply put a phone in a container and see if it rings when called. But this has a serious limitation: you likely don\u2019t know how far away the cell tower is, what frequency it\u2019s using, or its signal strength.\u201d<\/p>\n\n\n\n
\u201cA quick and likely reliable \u201cgo\/no go test\u201d can be done with an Apple AirTag and an iPhone: drop the AirTag in the bag under test, and see if the phone can locate it and activate its alarm (beware of caching in the FindMy app when doing this).\u201d<\/p>\n\n\n\n
Here\u2019s a crucial piece of advice: put your phone in the pouch before you set off to a place you want to keep secret, not when you arrive there. \u201cFor example, if you\u2019re concerned about being tracked to some sensitive meeting, you need to isolate the phone before traveling there, not merely once you\u2019ve arrived,\u201d says Blaze.<\/p>\n\n\n\nSignal<\/th> Who can catch it<\/th> What it reveals<\/th> How to turn it off<\/th> What you lose<\/th><\/tr><\/thead> Wi-Fi probes<\/td> Anyone nearby with a Wi-Fi receiver, including roadside sensors<\/td> Names of networks your phone has joined before; 23.2% of probes in the Hamburg study carried them<\/td> Turn Wi-Fi off in Settings, not Control Center (iPhone); delete saved hidden networks; on Android, turn on non-persistent MAC randomization in developer options<\/td> Automatic joining of known networks<\/td><\/tr> Bluetooth from phone<\/td> Anyone nearby with a Bluetooth receiver<\/td> Your device name, and a trackable presence<\/td> Turn Bluetooth off in Settings, not Control Center (iPhone)<\/td> Earbuds, watch and car connections<\/td><\/tr> Bluetooth from accessories<\/td> Anyone nearby with a Bluetooth receiver<\/td> Make and model (a Bose product, an Audi infotainment system); some devices never change their address<\/td> Unpair devices you no longer use; switch off the ones you don\u2019t need<\/td> The accessory, while it is off<\/td><\/tr> Background scanning<\/td> Google\u2019s location service, and anyone listening nearby<\/td> Your phone keeps scanning after you think the radios are off<\/td> Android: Settings > Location > Location Services, turn off Wi-Fi scanning and Bluetooth scanning; also turn off Improve Location Accuracy<\/td> Some location accuracy<\/td><\/tr> Device name<\/td> Anyone nearby on Bluetooth, a hotspot or AirDrop<\/td> Your name, if the phone carries it<\/td> iPhone: Settings > General > About > Name. Android: Settings > About phone > Device name, and rename the hotspot separately. Keep AirDrop on Contacts Only<\/td> Nothing much<\/td><\/tr> Find My offline finding<\/td> Apple\u2019s Find My and Google\u2019s Find Hub networks<\/td> Keeps an iPhone findable for up to 24 hours after it is turned off<\/td> iPhone: turn off Find My before powering off. Android: Settings > Google > All services > Find Hub > Find your offline devices > Off<\/td> Finding a lost or stolen phone<\/td><\/tr> Cellular \/ 2G<\/td> Cell-site simulators (fake cell towers)<\/td> Your subscriber number (IMSI) and device number (IMEI); 2G can be forced to run unencrypted<\/td> iPhone: Lockdown Mode only. Android 16: turn on 2G network protection. Samsung: Auto Blocker > Maximum restrictions<\/td> Service where only 2G is available; Lockdown Mode limits many other features<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nIn June, the US Supreme Court ruled<\/u><\/a> that police obtaining a person\u2019s location records from Google is a search. But the law has not caught up with a related question: what about sensors that listen to \u2013 and log \u2013 the signals broadcast by people\u2019s devices, as they walk or drive by?<\/p>\n\n\n\nThe opinion, written by Justice Elena Kagan, states, \u201cWhat creates that concern is that the government can access all of a cell-phone user\u2019s movements, in both public and private places \u2013 that it possesses a virtual panopticon with which to scrutinize its citizens\u2019 activities.\u201d<\/p>\n\n\n\n
<\/figure>\n\n\n\nBy Ken Macon<\/p>\n\n\n\n
On a seemingly ordinary road outside of Washington, DC, there are poles carrying gear that, according to its maker, logs the radio signals coming off phones, earbuds, and watches in passing cars, and ties this information to the car\u2019s license plate.<\/p>\n\n\n\n
In a post titled, \u201cThinking Critically About SignalTrace<\/u><\/a>\u201d \u2013 that was first published on August 2, 2026, and updated on September 18 \u2013 Ryan O\u2019Horo, who writes a blog on security, said he found four installations in Oxon Hill, Maryland, near National Harbor, on Oxon Hill Road and National Harbor Blvd, and that they are operated by the Prince George\u2019s County Police Department.<\/p>\n\n\n\n O\u2019Horo also found that \u201ca few hundred feet north, a Flock Safety ALPR camera<\/u><\/a> is installed.\u201d (Flock Safety is a company that makes automatic license plate readers, or ALPRs<\/u><\/a>.)<\/p>\n\n\n\n O\u2019Horo found two more installations, in Solomons and Dunkirk in Calvert County, Maryland, which are served by the Calvert County Sheriff\u2019s Department. He also published what he said was an invoice from June 2023 showing the sheriff\u2019s office bought two SignalTrace devices.<\/p>\n\n\n\n O\u2019Horo noted that the antennas are located in a way that allows them to pick up signals from devices carried by pedestrians, not just those in vehicles.<\/p>\n\n\n\n However, Reclaim The Net has not been able to confirm that the devices are actually in use, and that they are SignalTrace models.<\/p>\n\n\n\n What the devices do is not something that those driving past them would know.<\/p>\n\n\n\n The product page of SignalTrace, a surveillance tool made by Italy\u2019s Leonardo and sold to police in the US, has undergone changes in recent months \u2013 but the most important thing about it, its purpose, has remained the same.<\/p>\n\n\n\n The product page, as it stood in June 2026, was very clear and direct: \u201cIdentify Suspects by the Electronic Devices They Use.\u201d<\/p>\n\n\n\n At the same time, it was also clear that the product was not about the car itself, but the people in it \u2013 the pitch was about finding out who they are, by identifying their devices.<\/p>\n\n\n\n In June, the page said the product was \u201cdesigned to help law enforcement identify people of interest by the signals emitted from their electronic devices they travel with, such as fitness trackers, smartwatches, RFID tags, and local signals from their mobile phones.\u201d<\/p>\n\n\n\n When the reports first appeared in June<\/u><\/a>, no police department had been confirmed to have bought the product, but by late July, the \u201csuspects\u201d were gone from the product\u2019s page, and \u201cleads\u201d were in. And while the page still explains that the system can pinpoint a device by the unique signals it emits, the example given has been tweaked to remove the license plate, that was present in the June version.<\/p>\n\n\n\n On August 4, 2026, Leonardo announced the new name<\/u><\/a>. The company said: \u201cSignalTrace does not identify individuals, access communications or retrieve information stored on personal devices.\u201d<\/p>\n\n\n\n The New York City Police Department (NYPD) is preparing to spend three-quarters of a million dollars on a cell-site simulator<\/u><\/a> \u2013 a fake cell tower that vacuums up phone data of everyone in its vicinity.<\/p>\n\n\n\n The contract with an Israeli company Cognyte is worth $750,500 and will last for three years, the New York Daily News is reporting<\/u><\/a>.<\/p>\n\n\n\n The New York Civil Liberties Union (NYCLU) says this is \u201chighly intrusive\u201d and \u201cdragnet surveillance,\u201d and the new tech \u201cgoes even further by incorporating undisclosed AI capabilities that analyze people\u2019s behaviors.\u201d<\/p>\n\n\n\n The NYPD has a policy<\/u><\/a> that is supposed to regulate the use of cell-site simulators, and it says that a warrant is required, and that the technology will not be used to intercept content of communications.<\/p>\n\n\n\n Another exception to the warrant rule is if there\u2019s an emergency \u2013 but then the police must obtain the warrant within 48 hours. And there\u2019s also the \u201cmissing or suicidal person\u201d exception, when a search warrant is not required at all.<\/p>\n\n\n\n Your phone is a snitch, and it\u2019s a chatty one at that. While you are not using it, it keeps asking out loud for the networks it has known \u2013 and, in a real street, that \u201cloud\u201d announcement can leak passwords, names, and information about your holiday home.<\/p>\n\n\n\n Phones, when not connected to a Wi-Fi network, keep looking for one to connect to, and they do this by sending out what\u2019s known as a probe request.<\/p>\n\n\n\n The University of Hamburg\u2019s Johanna Ansohn McDougall and her colleagues<\/u><\/a> decided to see what exactly is happening in this process, and how much sensitive information is being leaked. They recorded the data sent out by phones in a busy street in a German city for an hour, three times.<\/p>\n\n\n\n The team found that 23.2 percent of the probe requests contained the names of the networks, known as SSIDs.<\/p>\n\n\n\n As the researchers note, \u201cusers (probably by accident) input a wealth of data into the SSID field and find passwords, e-mail addresses, names and holiday locations.\u201d<\/p>\n\n\n\n What\u2019s more, \u201can attacker could follow the owner of a talkative device to their home and try out the password in their home network.\u201d<\/p>\n\n\n\n Earbuds, watches, fitness bands and cars all broadcast short Bluetooth announcements all the time, so that phones can find them. And phones, in turn, rotate their Bluetooth addresses so that a listener sees a string of strangers rather than one device.<\/p>\n\n\n\n In 2019, a team from Boston University<\/u><\/a> (Johannes Becker, David Li, David Starobinski) wrote: \u201cwe show that many state-of-the-art devices which are implementing such anonymization measures are vulnerable to passive tracking that extends well beyond their address randomization cycles.\u201d<\/p>\n\n\n\n The team tested Fitbit watches and found that \u201cwhile the TxAdd flag indicates that the devices use random addresses, the addresses actually never change\u201d \u2013 and that \u201cthe smartwatch advertises approximately once every 7 seconds using this format.\u201d<\/p>\n\n\n\n O\u2019Horo says that \u201cBluetooth devices particularly tend to reveal the model in the device name, so even when they use BLE\u2019s address randomization feature, you could know you\u2019ve captured information about Bose product, or an infotainment system installed in an Audi.\u201d<\/p>\n\n\n\n Apple itself advises users<\/u><\/a>: \u201cYou can change the name of your iPhone, which is used by iCloud, AirDrop, Bluetooth\u00ae, your Personal Hotspot, and your computer.\u201d<\/p>\n\n\n\n If you name your iPhone Fred’s iPhone \u2013 that\u2019s what it will be announcing to the world as its Bluetooth name, its hotspot name, and on AirDrop.<\/p>\n\n\n\n When you switch off Wi-Fi and Bluetooth on your phone, they don\u2019t always stay switched off.<\/p>\n\n\n\n On Android, there\u2019s a setting that most people never chose but is enabled by default and keeps scanning for networks and devices even after you think you turned the radios off.<\/p>\n\n\n\n On iPhone, the Control Center\u2019s \u201cquick\u201d buttons<\/u><\/a> for Wi-Fi and Bluetooth don\u2019t actually switch them off, they just disconnect from the networks and devices they were connected to, but remain available for future connections, and the system will use them if it sees fit.<\/p>\n\n\n\n Then there\u2019s the cellular network. Your phone has to identify itself to it, and that\u2019s done by sending the subscriber number (IMSI) and device number (IMEI) to the network. The problem is that a fake cell tower will ask the same questions, and the phone will provide the same answers.<\/p>\n\n\n\n This is why, as Google\u2019s Android security team has noted<\/u><\/a>, it\u2019s easy to \u201cpush\u201d a phone down to 2G, where the \u201cattackers abuse the well known lack of mutual authentication in 2G and force connections to be unencrypted.\u201d<\/p>\n\n\n\n In other words, 2G is an open door that, if not closed, can be easily exploited. It\u2019s not a question of whether your carrier still uses 2G in your area or not, because \u201cusers are still vulnerable to this type of fraud as long as mobile devices support 2G, regardless of the status of 2G in their local carrier,\u201d the Android team warned.<\/p>\n\n\n\n O\u2019Horo says that SignalTrace can likely only collect data from Wi-Fi, Bluetooth, and certain 915MHz RFID devices \u2013 but not from every device, and not every time, given that cars are moving and all.<\/p>\n\n\n\n Newer phones do randomize their MAC addresses, and their signals are brief and \u201chopped\u201d across different channels, which means that a roadside sensor is only getting fragments of data. But randomization is not the solution to the problem of device tracking. In 2016, Mathy Vanhoef and colleagues published a paper<\/u><\/a> that showed that this method \u201cdoes not guarantee privacy.\u201d<\/p>\n\n\n\n The end result is that it is the people using cheaper and older devices who are least protected from tracking, as O\u2019Horo noted: \u201cThis also creates an economic inequity. More modern and expensive devices defend against tracking better, including devices in more expensive vehicles.\u201d<\/p>\n\n\n\n Many of the iPhone \u201cfixes\u201d to make the device less trackable cost absolutely nothing.<\/p>\n\n\n\n For one thing, those \u201cconvenience\u201d buttons in the iPhone\u2019s Control Center don\u2019t actually turn off the device\u2019s radios. Settings does.<\/p>\n\n\n\n If you want to turn off Wi-Fi and Bluetooth, don\u2019t do it from the Control Center \u2013 instead, go to Settings, then Wi-Fi, and turn it off there. The same goes for Bluetooth.<\/p>\n\n\n\n If you\u2019re using iOS 18 or a later version, you can make the device rotate the Wi-Fi address it uses to connect to a network<\/u><\/a>. To do this, go to Settings, Wi-Fi, tap the More Info button next to the network you\u2019re connected to, then go to Private Wi-Fi Address, and turn it on. You can choose to have the address rotate every two weeks, or keep it fixed. Apple advises that a fixed address is used by default when joining a network that uses WPA2 or stronger security. The company also explains that if the device always uses the same address across all networks, observers can more easily identify it and track its activity and location.<\/p>\n\n\n\n If you have any hidden networks saved, delete them, because the phone has to call out the name of a hidden network to find it.<\/p>\n\n\n\n There are a few more things you can do in Settings to make your iPhone a little less trackable. One is to rename the device. You can do this by going to Settings, General, About, Name. Apple says the name is \u201cused by iCloud, AirDrop, Bluetooth\u00ae, your Personal Hotspot, and your computer.\u201d So renaming it to something not very descriptive of you or your device would be a good idea. This will also rename your hotspot.<\/p>\n\n\n\n You can never truly \u201cturn off\u201d an iPhone \u2013 but there are trade-offs.<\/p>\n\n\n\n Find My, which keeps an iPhone \u201cdiscoverable\u201d for up to 24 hours after it\u2019s been turned off, is useful if the phone is stolen \u2013 but it also means the phone is never really off.<\/p>\n\n\n\n Apple has instructions on how to turn off Find My<\/u><\/a> on a device before switching it off, and you can also do it by tapping on the note that appears on the power-off screen.<\/p>\n\n\n\n Then there\u2019s Lockdown Mode, which is the only way to turn off 2G on an iPhone \u2013 but it\u2019s a heavy tool that should not be used lightly.<\/p>\n\n\n\n Apple itself says that Lockdown Mode<\/u><\/a> is \u201can optional, extreme protection that\u2019s designed for the very few individuals who, because of who they are or what they do, might be personally targeted by some of the most sophisticated digital threats. Most people are never targeted by attacks of this nature.\u201d<\/p>\n\n\n\n Those who might be \u201cpersonally targeted by some of the most sophisticated digital threats\u201d would be reasonable candidates for using Lockdown Mode \u2013 that means journalists, activists, and anyone with a reason to believe they are a target. Not someone who simply wants to reduce their general exposure to tracking.<\/p>\n\n\n\n For those who are, or might soon become a target, Lockdown Mode can be found here: Settings, Privacy & Security, Lockdown Mode.<\/p>\n\n\n\n As for AirDrop, it should be kept on Contacts Only, and never set to \u201ceveryone.\u201d This can be done by opening the Control Center, touching and holding the top-left controls, tapping AirDrop, and choosing Contacts Only.<\/p>\n\n\n\n Ultimately, the choice is yours.<\/p>\n\n\n\n Your first job after setting up your new Android device is to undo a setting it switched on for you.<\/p>\n\n\n\n We\u2019ll get to what that is in a moment, but first, some advice: go into Settings, Location, Location Services, and turn off both Wi-Fi scanning and Bluetooth scanning. On Android 11 and older, these are located directly under Settings, Location.<\/p>\n\n\n\n You do this because these two are switched on by default, as a Google note from 2018 reveals<\/u><\/a>, and as confirmed by GrapheneOS, which is an Android distribution that ships with these settings off.<\/p>\n\n\n\n While you\u2019re there, turn off Improve Location Accuracy. Google itself said that \u201cWhen Location Accuracy is on, Google periodically collects information about sensors and wireless signals near you to contribute to crowdsourced wireless signal locations.\u201d<\/p>\n\n\n\n Another thing to change is the device name that\u2019s broadcast by Wi-Fi and Bluetooth. Go to Settings, About phone, Device name, and change it from whatever it is to whatever you want it to be. The name of the hotspot is changed in a different place: Settings, Network & internet, Hotspot & tethering, Wi-Fi hotspot, Hotspot name.<\/p>\n\n\n\n Next, make sure that the MAC address of your device is randomized. Android\u2019s own documentation says<\/u><\/a> that \u201cBy default, Android uses persistent randomization.\u201d But persistent means it doesn\u2019t actually change, ever. As the documentation also has it, \u201cThis MAC address remains the same until a factory reset.\u201d It doesn\u2019t even change if you forget a network and then re-add it.<\/p>\n\n\n\n If you want your MAC address to actually change each time you connect to a network, you have to go to the developer options and enable \u201cWi-Fi non-persistent MAC randomization.\u201d<\/p>\n\n\n\n The latest Android version, Android 16, brings several security and privacy features, but also one that is not immediately obvious: the 2G switch has been flipped.<\/p>\n\n\n\n Instead of turning 2G off, as was the case in Android 12 to 15, now you turn 2G network protection on<\/u><\/a>.<\/p>\n\n\n\n The new setting is in Settings, Network & internet, SIMs, 2G network protection.<\/p>\n\n\n\n Not all phones running Android 16 will have this setting, however. Samsung phones, for example, don\u2019t have a separate 2G switch; on One UI 6.1.1 and later, it is part of Settings, Security and privacy, Auto Blocker, Maximum restrictions. Samsung also warns<\/u><\/a> that turning it on may interfere with calls, messages, and mobile data in areas where only 2G service is available.<\/p>\n\n\n\n Android 16 has also added a new section, Mobile network security, which can show notifications when the phone connects to an unencrypted network or is asked for its IMSI or IMEI. But the latter requires modem support, which, according to a 2025 report by the German site teltarif<\/u><\/a>, current Pixels lack.<\/p>\n\n\n\n Then there is the ability to find devices even when they are offline. This is the same trade-off that Apple\u2019s Find My iPhone has been making for years, and Google is not shy to admit it.<\/p>\n\n\n\n \u201cBy default, your Android device stores encrypted recent locations with Google and participates in the Find Hub network,\u201d Google\u2019s documentation reads<\/u><\/a>.<\/p>\n\n\n\n You can turn this off, but it is on by default.<\/p>\n\n\n\n To do so, go to Settings, Google, All services, Find Hub, Find your offline devices. Then, you can choose from Off, Without network, With network in busy places only, and With network everywhere.<\/p>\n\n\n\n For those willing to go the extra mile, there is GrapheneOS, a privacy and security-focused mobile operating system that is a hardened version of Android, and can run on Pixel phones.<\/p>\n\n\n\n GrapheneOS gives a new random Wi-Fi address on every connection<\/u><\/a>: \u201cGrapheneOS supports per-connection MAC randomization and enables it by default.\u201d<\/p>\n\n\n\n If you have a reliable LTE connection, GrapheneOS advises<\/u><\/a>, \u201cyou can reduce attack surface by disabling 2G, 3G and 5G connectivity in Settings > Network & internet > SIMs > SIM > Preferred network type.\u201d<\/p>\n\n\n\n You might be able to switch your phone off, or put it in airplane mode, and if you can, you should \u2013 but what about all the other devices that are now attached to you and the car?<\/p>\n\n\n\n You can unpair devices you no longer use, and switch off those you don\u2019t need at a particular time.<\/p>\n\n\n\n What about the car itself?<\/p>\n\n\n\n You can check its settings to see if its own Wi-Fi hotspot can be switched off, and if it can, do that \u2013 unless you absolutely need it, in which case at least make sure to change its name to something that doesn\u2019t reveal your identity.<\/p>\n\n\n\n Then there are the tire sensors. They will keep shouting their ID, a fixed number, whatever you do.<\/p>\n\n\n\n IMDEA Networks researchers and their colleagues said in a paper in 2026<\/u><\/a> that these sensors send out signals with a unique identifier that doesn\u2019t change over \u201cvery long periods of time.\u201d<\/p>\n\n\n\n \u201cBecause each sensor broadcasts a fixed unique ID, the same car can be recognized repeatedly without reading a license plate,\u201d the researchers said in a press release<\/u><\/a>.<\/p>\n\n\n\n Yago Lizarribar, one of the authors, said that tire pressure monitoring system (TPMS) was \u201cdesigned for safety, not security.\u201d<\/p>\n\n\n\n The only real off switch is a good Faraday pouch.<\/p>\n\n\n\n Airplane mode is not an off switch \u2013 it\u2019s a button with a misleading name. Apple\u2019s support website says<\/u><\/a> that on an iPhone, \u201cthis turns off all radios except for Bluetooth.\u201d And even that statement is not entirely true, because, as Apple also notes, \u201cif the airline allows it, you can still use Wi-Fi and Bluetooth in Airplane Mode.\u201d<\/p>\n\n\n\n So \u2013 a Faraday pouch it is. But not just any will do. In 2021, security researcher Matt Blaze tested several<\/u><\/a>, and the cheap ones, like mylar bags, didn\u2019t do well: \u201cIn no instance did any of my mylar\/ESD bags provide more than about 9 dB of attenuation.\u201d<\/p>\n\n\n\n Blaze also warned against a weak test of the pouch\u2019s effectiveness: \u201cA less useful test is to simply put a phone in a container and see if it rings when called. But this has a serious limitation: you likely don\u2019t know how far away the cell tower is, what frequency it\u2019s using, or its signal strength.\u201d<\/p>\n\n\n\n \u201cA quick and likely reliable \u201cgo\/no go test\u201d can be done with an Apple AirTag and an iPhone: drop the AirTag in the bag under test, and see if the phone can locate it and activate its alarm (beware of caching in the FindMy app when doing this).\u201d<\/p>\n\n\n\n Here\u2019s a crucial piece of advice: put your phone in the pouch before you set off to a place you want to keep secret, not when you arrive there. \u201cFor example, if you\u2019re concerned about being tracked to some sensitive meeting, you need to isolate the phone before traveling there, not merely once you\u2019ve arrived,\u201d says Blaze.<\/p>\n\n\n\n In June, the US Supreme Court ruled<\/u><\/a> that police obtaining a person\u2019s location records from Google is a search. But the law has not caught up with a related question: what about sensors that listen to \u2013 and log \u2013 the signals broadcast by people\u2019s devices, as they walk or drive by?<\/p>\n\n\n\n The opinion, written by Justice Elena Kagan, states, \u201cWhat creates that concern is that the government can access all of a cell-phone user\u2019s movements, in both public and private places \u2013 that it possesses a virtual panopticon with which to scrutinize its citizens\u2019 activities.\u201d<\/p>\n\n\n\n<\/figure>\n\n\n\nSignal<\/th> Who can catch it<\/th> What it reveals<\/th> How to turn it off<\/th> What you lose<\/th><\/tr><\/thead> Wi-Fi probes<\/td> Anyone nearby with a Wi-Fi receiver, including roadside sensors<\/td> Names of networks your phone has joined before; 23.2% of probes in the Hamburg study carried them<\/td> Turn Wi-Fi off in Settings, not Control Center (iPhone); delete saved hidden networks; on Android, turn on non-persistent MAC randomization in developer options<\/td> Automatic joining of known networks<\/td><\/tr> Bluetooth from phone<\/td> Anyone nearby with a Bluetooth receiver<\/td> Your device name, and a trackable presence<\/td> Turn Bluetooth off in Settings, not Control Center (iPhone)<\/td> Earbuds, watch and car connections<\/td><\/tr> Bluetooth from accessories<\/td> Anyone nearby with a Bluetooth receiver<\/td> Make and model (a Bose product, an Audi infotainment system); some devices never change their address<\/td> Unpair devices you no longer use; switch off the ones you don\u2019t need<\/td> The accessory, while it is off<\/td><\/tr> Background scanning<\/td> Google\u2019s location service, and anyone listening nearby<\/td> Your phone keeps scanning after you think the radios are off<\/td> Android: Settings > Location > Location Services, turn off Wi-Fi scanning and Bluetooth scanning; also turn off Improve Location Accuracy<\/td> Some location accuracy<\/td><\/tr> Device name<\/td> Anyone nearby on Bluetooth, a hotspot or AirDrop<\/td> Your name, if the phone carries it<\/td> iPhone: Settings > General > About > Name. Android: Settings > About phone > Device name, and rename the hotspot separately. Keep AirDrop on Contacts Only<\/td> Nothing much<\/td><\/tr> Find My offline finding<\/td> Apple\u2019s Find My and Google\u2019s Find Hub networks<\/td> Keeps an iPhone findable for up to 24 hours after it is turned off<\/td> iPhone: turn off Find My before powering off. Android: Settings > Google > All services > Find Hub > Find your offline devices > Off<\/td> Finding a lost or stolen phone<\/td><\/tr> Cellular \/ 2G<\/td> Cell-site simulators (fake cell towers)<\/td> Your subscriber number (IMSI) and device number (IMEI); 2G can be forced to run unencrypted<\/td> iPhone: Lockdown Mode only. Android 16: turn on 2G network protection. Samsung: Auto Blocker > Maximum restrictions<\/td> Service where only 2G is available; Lockdown Mode limits many other features<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n