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Privacy Phones By Dr David Maddison, VK3DSM The modern smartphone can be very useful, allowing you to look up information just about anywhere, navigate to unknown places, take photos, watch videos, send and receive messages and more. It can also let all sorts of entities track you, from megacompanies like Google, Meta (Facebook), Microsoft and Apple to phone companies, the government & even criminals. What can you do about that? Image source: Dan Nelson – siliconchip.au/link/abv2 O ne of the things you can do is use a ‘privacy phone’, a smartphone designed to reduce the ability for third parties to track you. Note, though, that there’s no way of stopping phone companies or the government from tracking you if you have a mobile phone. Such devices are therefore mainly focused on preventing the harvesting of your personal information by ‘big tech’ (generally regarded as Google, Apple, Microsoft & Meta). It is possible to buy a privacy phone but you can also turn certain brands and models of Android phones into a privacy phone yourself. Information that ‘big tech’ gathers includes your location, how often and when you visit such places, what you search for, what videos you watch, who your contacts are, the contents of your text messages or emails and any other information that may be used to target you for particular types of advertising or services, or to sell to third parties for profit. 16 Silicon Chip Some information they harvest might also be passed onto the government in response to a warrant (or possibly without one, depending on their ethics or lack thereof). Have you ever used a popular search engine to search for a product or service and then found yourself bombarded with advertisements on social media, video platforms, or other search results for that product? It’s a commonly reported situation that demonstrates how much information is being collected. Before we get to the phones and software that can improve your privacy, let’s examine why that is a good idea. It’s important for us to state that while we do our best to make these articles comprehensive, we cannot cover every single edge case. What information is collected about you? Just about any information entered via your phone or computer is liable Australia's electronics magazine to be collected and used (or misused) by third parties. Apart from the examples mentioned above, that includes (but is not limited to): ● Name ● Email address ● Birth date ● Gender ● Phone number ● IP address(es) ● Places you visit ● Your interests, based on your web history, search history and the content of anything you post or even what is included in private emails ● Your political & other affiliations ● Websites you visit ● Videos you watch ● People you engage with ● Device information such as type, operating system (OS), type of browser and other apps ● Cookies stored by your web browser ● Which advertisements you watch or ignore siliconchip.com.au Are privacy phones liable for misuse? Any technology is open to abuse. Those with nefarious intentions certainly might benefit from phones (and other devices) that limit monitoring and eavesdropping. However, the main beneficiaries of privacy phones are intended to be normal, regular people. You don’t have to be an ‘interesting’ or high-profile person for your data to be routinely vacuumed up and stored, to be possibly used or misused in the future. In this article, we discuss the types of information that might be collected about you and what you can do to enhance your privacy. ● Which advertisements you click on ● The contents of messages, chats etc Where is your private data intercepted? Your data can be intercepted on the phone network, the web servers you access, or via apps you use, such as social media or search engines. A mobile phone connects to the world via two channels. One is the telephone network (via a mobile phone tower) for voice traffic and SMS (text messages). The other is via the internet (either via a tower or WiFi) – see Fig.1. It is possible for data to be intercepted over either network, although it more commonly occurs on the internet. Voice calls can be made over the mobile or PSTN (publicly switched telephone network) telephone network or using VoIP (voice over internet protocol), an application of SIP (session initiation protocol). The latter calls are made via the internet and do not require a mobile connection if WiFi is available. A VoIP phone on a private network can make calls to regular PSTN numbers using a SIP trunk provider. Big tech social media and search engines log your activities, which is probably the most common way your data is harvested. Note also that anything you say in a video that’s posted publicly (eg, on YouTube or Facebook) is also converted to text, which can be read by humans or artificially intelligent (AI) bots. Text in photos you post can also be converted to text and scanned. Photos you post or store ‘in the cloud’, or even those stored on your mobile device, can also have facial recognition applied, and they can figure out who the people are in your photos and thus form associations between you and others. siliconchip.com.au It isn’t just big tech that can intercept your data; state actors or malicious hackers can too. All phone call and text message ‘metadata’, such as who called whom, when, where, call duration and other parameters, are routinely collected. In Australia, it is a government requirement. The EU tried implementing similar data-gathering methods, but they were not well-received. The following 11-year-old video on the topic drew a lot of attention to phone privacy issues. It is named “Malte Spitz: Your phone company is watching” and can be viewed at https://youtu.be/Gv7Y 0W0xmYQ Why some apps are free Nothing is truly free and phone apps are no exception. Except for open-source software, if an app is free, that is probably because your data is being collected and sold through the app. Most private data that’s sold was actually handed over willingly by the subject, knowingly or unknowingly! Most apps downloaded via the Google Play Store or Apple App Store are required to show what data they collect. We do not deny that Google, Facebook and others offer valuable services. For many or even most people, the harvesting of your data is the price you pay for the services provided; some even appreciate the targeted advertising that results. These multi-billion-dollar companies have to earn an income somehow. Facebook We are not singling out Facebook but it is a widely used app that provides a good example of the sort of information of interest to social media businesses. Facebook uses machine learning to analyse your activities on Facebook and generate ads based upon such criteria as: ● What you have ‘liked’ ● Which ads you have clicked on ● Your activities on Instagram ● Age, gender, location and the devices you use to access Facebook ● Information that advertisers, their partners and marketing partners share with Facebook that they already have, like your email address and your activity on websites and apps off of Facebook If you wonder why you saw a particular ad on Facebook, you can click on the three dots and click on “Why am I seeing this ad?” to see why Facebook targeted it at you. For further information on this, see siliconchip. au/link/abv1 Facebook also analyses the content of your photos. For every photo a user uploads, it is said they identify people, objects, background scenes, the moods of people and their postures, animals (see Fig.2), location such as inside/outside, the geographic Fig.1: the basic configuration of a mobile (cellular) communications network. Original source: https://doi.org/10.3390/s23010352 (CC-BY-4.0). Australia's electronics magazine June 2024  17 Fig.2: examples of Facebook AI recognising animals in photos. Source: www. digitaltrends.com/web/facebook-ai-image-recognition/ location, activities such as relaxing by the pool. They store all the detected characteristics in an associated file (see siliconchip.au/link/abud). Facebook also uses its DeepFace facial recognition engine (Fig.3), which is said to be more accurate than the FBI’s. It can be used to tag friends in photos and can also detect if someone has stolen your profile photo, among other uses. Facebook uses AI to detect and delete inappropriate photos; they say they don’t use the phone’s microphone or text messages to generate ads. Facebook marketing tools allow the promotion of products according to: ● Region or population density ● Age, gender, marital status, family status and occupation ● Brand loyalty or user status ● Social status (eg, lower, middle or upper class) ● Interests, according to keywords used in searches ● Interests that intersect with the common pursuits of a chosen group That indicates the level of information being collected (see siliconchip. au/link/abus). Creating a social network map can also be valuable for marketers (see siliconchip.au/link/abuz). Google Again, we are not singling out any one company, but Google’s business model is based on harvesting data from users and selling it to advertisers. Google (and others) also harvest location data via SUPL (Secure User Plane Location) – see siliconchip.au/ link/abur Does big tech listen in on you for marketing purposes? Fig.3: Facebook’s DeepFace image recognition engine is said to be more accurate than the FBI’s. Source: www.facebook.com/photo?fbid=689135484598987 18 Silicon Chip Australia's electronics magazine Facebook and Instagram write: “We understand that sometimes ads can be so specific, it seems like we must be listening to your conversations through your microphone, but we’re not. We only use your microphone if you’ve given us permission and are actively using a feature that requires the microphone.” If you use Google Assistant, your phone is always listening and waiting for commands. However, Google says it does not listen to conversations to generate targeted advertisements. The Amazon Alexa is an example of a device that did use recordings to generate targeted adverts: siliconchip. au/link/abv0 siliconchip.com.au This is a contentious issue. Some people do not believe these denials. Others believe them and say that these companies know so much about you that their accurate predictive advertising makes it seem like you are being listened to. Apple While they have been criticised for various reasons (including by us in the past), Apple has pretty good privacy protections. They do not sell your data to advertisers, although they may use it internally. They offer end-to-end encryption on cloud services, do not embed trackers in third-party websites like Google, tracking between apps is ‘opt-in’, and they have many other privacy and security features (see siliconchip.au/link/abut). On the other hand, Apple’s phones are more expensive than many Android phones, and it seems they want you to replace them as often as possible (eg, by locking you into using their expensive replacement parts, including batteries). An iPhone can be de-Googled if you change the default browser to Safari and choose a privacy-focused search engine. If you use any app that uses Google for advertising, you will be connected to Google, although you can select “Ask App Not to Track”. Apple provides information about privacy and location services in iOS, iPadOS and watchOS at https:// support.apple.com/en-au/102515 For maximum privacy on Apple phones, it is important that you turn off settings that may compromise your privacy. Apple maintains that they have no ‘backdoor’ to decrypt data on an iPhone, not even in cases of national security: Apple has never created a backdoor or master key to any of our products or services. We have also never allowed any government direct access to Apple servers. And we never will – www. apple.com/privacy/governmentinformation-requests/ Security expert Rob Braxman has an alternative viewpoint. He says that Apple’s use of AI and ‘client-side scanning’ can reveal the contents of a phone before encryption. For example, a description of the content of certain photos might be generated by the phone, such as a person matching a particular description. siliconchip.com.au How much does privacy matter (to you)? Some people may be unconcerned with privacy issues and do not want a privacy phone or enhanced privacy on an ordinary phone. Everyone has their own opinion on such matters. After all, some people keep their windows covered at all times, while others leave the blinds open, even at night. Edward Snowden said, “Arguing that you don’t care about the right to privacy because you have nothing to hide is no different than saying you don’t care about free speech because you have nothing to say”. Most philosophers consider privacy a basic human right in a free society. Article 12 of the United Nations’ Universal Declaration of Human Rights states, “No one shall be subjected to arbitrary interference with his privacy...”. Even if you aren’t concerned about what big tech is doing with the data they gather on you, consider what would happen if they are hacked and the data makes its way onto the ‘dark web’ (as seems to happen often). The people who ultimately get a hold of that data may not have the best ethics or morals... In theory, that could be passed onto authorities, not necessarily benign ones, in the case of a dictatorial country. For more on this theory, see his video titled “Apple Now Has a Backdoor to Bypass Encryption!” at https:// youtu.be/Mg4HWEdar2Q Also see his video channels at: • www.youtube.com/<at> robbraxmantech • https://odysee.com/<at> RobBraxmanTech:6 • rumble.com/c/robbraxman Location tracking Your location is a valuable commodity to marketers. ‘Geofence marketing’ or geomarketing is a type of location-based marketing that targets consumers once they enter a particular geographically defined area (see Fig.4). You could receive advertisements via SMS, push notifications, Facebook advertisements or other advertisements describing promotions on offer in the area they have entered. The user’s location is tracked via a phone’s GPS, WiFi, Bluetooth or RFID. The consumer would (possibly unknowingly) have given permission for their location to be shared by various apps they use. Even after you have left a geofenced area, you may continue to receive advertisements because you have shown an interest in that area. This period may be up to 30 days (as per siliconchip.au/link/abuu). Google offers its customers a Geofencing API (application programming interface) to assist marketers in tracking customers. With a non-privacy phone, you are liable to give away location data that Fig.4: an example of geofence marketing by Propellant Media. Source: https:// propellant.media/geofencing-marketing-company-providers/ Australia's electronics magazine June 2024  19 Avoiding telemarketing calls and scams One way to enhance your privacy is to prevent telemarketers, scammers and others from getting your phone number. For some advice on how to achieve that, see www.acma.gov.au/make-your-phone-number-more-private can be used for marketing. Even if you turn location tracking off, your device can still be tracked by its IP address unless you use a VPN. If you use aeroplane mode, you can avoid being tracked, but you will also be unable to make or receive calls or use apps. In the USA, the FBI used geofencing to identify alleged rioters. Geofencing can also send notifications if a child with a device leaves a designated area. It can be used by home automation systems to turn appliances on or off when you arrive at home or leave. Certain car manufacturers such as BMW, Mercedes, Tesla and VW use geofencing to send the owner an alert if the car is moved. For more details, watch Naomi Brockwell’s video titled “You’re LEAKING Your LOCATION!” at https://youtu.be/A9DPDE0FZeQ reading, activities such as being at a gym or based on the videos you have been watching. Predictive advertising Privacy-respecting search engines ● Brave Search: https://search. brave.com/ ● Disconnect Search: https://search. disconnect.me/ ● DuckDuckGo: https://duckduckgo. com/ ● Gibiru: https://gibiru.com ● MetaGer: https://metager.org Google and Facebook generate ads according to your search history, browsing history and profile. They use machine learning to ‘know’ more about you the more you use the platforms by observing your behaviour and travels. They can target advertisements depending on what you are Enhancing your privacy Many people are fine with big tech collecting information about them, but what can you do if you don’t want to become a ‘data mine’? The main things you can do are to stop using certain apps, use a phone where the ability to harvest your data has been removed at the operating system level (a privacy phone) and use a VPN. Stop using certain apps Privacy experts say that the first step to privacy is to stop using Google services, any apps that use Google advertising services and Facebook. It is also essential to use privacy-focused search engines, email and browser apps. Fig.5: features of the privacy-focused Proton Mail service. 20 Silicon Chip Australia's electronics magazine ● Mojeek: www.mojeek.com ● Qwant: www.qwant.com ● searX: https://searx.thegpm.org ● Startpage: www.startpage.com ● Swisscows: https://swisscows. com/en Be aware that search results from big tech search engines like Google typically have built-in biases and rank the search results accordingly, not necessarily in terms of the truth of answers (eg, they will put advertisers at the top of the results, even if they are less relevant to your search terms). Privacy-respecting email services ● ProtonMail: https://proton.me/ mail (free for small users; see Fig.5) ● Tuta: https://tuta.com (also free for small users) ● Posteo: https://posteo.de/en ● Private-Mail: https://privatemail. com ● StartMail: www.startmail.com ● CounterMail: https://countermail. com Note that if you send an email from one of these services to, say, Gmail, Google will still know its contents. Privacy-respecting browsers Some browsers, especially popular ones like Chrome, send information to websites you visit, including what hardware you use – see Fig.6. Cookies are downloaded by your browser when you visit a website. Notionally, they store preferences, login details etc, but they can also be used to track you across websites. Some browsers have settings to block ‘tracking cookies’ or will do it by default. Apple’s Safari browser (www. apple.com/au/safari/) is considered a privacy-­focused browser, but it is closed source and no longer available on Windows. Brave browser (https://brave.com/) is the best, according to Naomi Brockwell (www.youtube.com/<at>Naomi BrockwellTV & https://odysee.com/<at> NaomiBrockwell:4). You can watch her video titled “ESSENTIAL Privacy Tools” at https://youtu.be/V6yu0JN NtRw Firefox (www.mozilla.org/en-US/ firefox/new/) has features like cookie blocking, privacy extensions and settings, including a “Facebook container” to make it harder for Facebook to track users. There is also Tor (www.torproject. org), but it is slower than most normal siliconchip.com.au browsers. There are also many variants of existing browsers like Ungoogled Chromium, GNU IceCat etc. Privacy-respecting messaging apps Signal (https://signal.org) is regarded as a private and secure free messaging app. Alternatives include Telegram. Using a privacy phone The general consensus among privacy experts is that you should use a ‘de-Googled’ (privacy) phone and apps. They also say not to use social media apps; after all, the purpose of social media apps is to publicise you, not keep you private. A ‘de-Googled’ phone is usually an Android phone with Google services removed. The Android operating system was developed by Google and is based on Linux. It is available in two versions: the free and open-source Android Open Source Project (AOSP), or the non-open source version built into most phones, containing closedsource code such as Google Mobile Services. Google Mobile Services includes Google Search, Chrome, YouTube, Google Play, Google Drive, Gmail, Google Meet, Google Maps, Google Photos, Google TV, YouTube Music and Firebase Cloud Messaging. All of these apps are removed from privacy phones. Not all Android phones can be de-Googled. You need a phone where the existing operating system can be replaced with a non-Google version of Android. We will discuss that shortly. Fig.6: a comparison of web browser privacy features using the default settings. Source: https://brave.com Using a VPN Privacy phones A VPN (virtual private network) is a service through which you route your data instead of via your own ISP (internet service provider). Your data passes through an encrypted tunnel to the VPN server, so its contents are kept secret. It is then decrypted and routed through the internet from their end, then routed back to you through the same encrypted tunnel. VPNs are often used as a privacy measure as they obscure the source of the internet traffic. They can also allow you to access ‘geo-blocked’ content, like videos, that can’t be accessed from your country. Some people seem to think that using a VPN ensures your privacy, but really, it’s only a small part of the puzzle. VPNs have to be chosen well, as Some phones are manufactured as privacy phones, while others are standard phones with a new OS installed. One solution adopted by many users who want privacy is to use a ‘dumb phone’, much like the original mobile phones. One downside of not owning a smartphone is that it makes certain transactions impossible. For example, many shows or events now require the presentation of an electronic ticket. No paper ticket is offered, so you must possess a smartphone for entry. Your old dumb phone is not likely to be usable now as it probably used 1G, 2G (GSM) or 3G have limited or no support now. Examples of dumb phones that support 4G or 5G and are available for purchase in Australia siliconchip.com.au stated by Naomi Brockwell. She suggests using a Swiss-based VPN like ProtonVPN as they have strong privacy laws. Her video titled “The DARK side of VPNs” can be viewed at https:// youtu.be/8MHBMdTBlok Also see siliconchip.au/link/abux (PDF) and siliconchip.au/link/abuy (how to bypass geo-blocking for online shopping and streaming by Choice). Mullvad VPN (https://mullvad. net) can also be a good choice due to not requiring any details to make an account and being payable in cash. Australia's electronics magazine are the Nokia 8210 4G (Fig.7), Nokia 105 4G; Nokia 2660/2720/5710, Cat S22 Flip, Opel Mobile Lite (and similar models), Aspera F46/F48/R40 and Uniwa V202T. Purpose-built privacy smartphones Some phones that are purpose-built with privacy in mind include: ● The Bittium Tough Mobile 2C (Fig.8, siliconchip.au/link/abue) has Android 11 (the latest version is 14) with enhanced security, with or without Google Mobile Services, and data is strongly encrypted. It has a backup battery, so tampering can be detected even with a flat main battery, including Fig.7: the Nokia 8210 4G ‘dumb phone’. This classic design has been updated to support 4G networks. Source: https://w. wiki/9qRW (CC-BY-SA 4.0). June 2024  21 physical intrusion. The microphones, Bluetooth and camera can be disabled with a button press. ● The ClearPHONE (Fig.9, www. clearunited.com) runs the de-­Googled ClearOS, based on Android 10 but with a private key. There is more information in this video: siliconchip.au/ link/abuf ● The KryptAll K iPhone (Fig.10, www.kryptall.com) strongly encrypts voice calls and is said to be used by heads of state. It appears to be an Apple iPhone with modified firmware. ● The Purism Liberty Phone (Fig.11, https://puri.sm/) runs the de-Googled PureOS. They also make privacy-­ focused tablets and portable computers. ● The Murena 2 (Fig.12, siliconchip. au/link/abug) is a privacy smartphone that uses the de-Googled /e/OS. They write, “Murena aims to free people from the Big Tech control over our personal data.” ● Punkt (Fig.13, www.punkt.ch/ en/) makes the MP02, a “minimalist phone” reminiscent of a dumb phone. However, it can share a data connection with a laptop or other device and make encrypted VoIP voice calls using the Signal protocol. They also make the MC02 “smarter phone” (Fig.14), which resembles a traditional smartphone and uses the de-Googled Apostrophy OS or AphyOS. ● The UP Phone (Fig.15, www. unplugged.com) runs a proprietary version of the de-Googled LibertOS. It is to be released in May 2024. They write, “The company is on a mission to stem the tide against Big Tech and Big Government, by making privacy accessible and convenient for everyone”. Phones that can be turned into privacy phones While we know it is challenging to modify iPhones, many Android phones also cannot be easily altered. Generally, to make a phone into a privacy phone, it must have an unlocked bootloader. Some phone brands with that capability are easier to modify than others; see the list at https://w. wiki/9qQk Surprisingly, Pixel phones from Google are said to be the best for installing custom privacy-focused Android OSs, a process known as installing a custom ROM. Which phones can be de-Googled also depends on the version of the privacy OS that is to be used. Each operating system has a website with a list of compatible phones (see below). Buying a de-Googled phone If you don’t want to be involved in the (possibly) challenging process of installing custom firmware on a phone, many companies sell new phones, such as the Pixel, with the process already done for you (see Fig.16). If you are interested in that, try searching for “privacy phones Australia” (without quotes) via DuckDuckGo or Google. Three we found (but have not purchased from) are: • aussecurityproducts.com.au • privacyphone.com.au • threecats.com.au Privacy Android OSs Here are some options to consider if Fig.15: the UP Phone runs a proprietary version of LibertOS. you want to reflash your phone with a privacy OS. Before making any changes, make sure you research the consequences of doing so and back up all your important data beforehand! If something goes wrong when reflashing your OS, it may be possible to ‘brick’ your device. If that concerns you, buying a pre-made device is probably a better option. The following are all open-source and free to use: ● CalyxOS (https://calyxos.org) supports some Fairphone, Pixel and Motorola phones. It is open-source and free. ● Divestos (https://divestos.org) supports many devices; see https:// divestos.org/pages/devices ● /e/OS (https://e.foundation/eosphone-welcome) is a fork of LineageOS. It supports some Gigaset, Fairphone, Samsung, Pixel, OnePlus and Teracube phones. ● GrapheneOS (https://grapheneos. org) only officially supports Google Pixel devices. Figs.8-12 (from left-to-right): the Bittium Tough Mobile 2C privacy phone runs Android 11 with enhanced security; the ClearPHONE runs ClearOS, which is based on Android 10; the KryptAll K iPhone is unusual in that it appears to be an Apple iPhone with its firmware modified to improve privacy and security; the Purism Liberty Phone runs PureOS, which is based on Linux (Android is as well); the Murena 2 runs /e/OS, a fork of LineageOS which, in turn, is based on Android. 22 Silicon Chip Australia's electronics magazine siliconchip.com.au Fig.16: a deGoogled Pixel phone with Proton and other privacyrespecting apps. Source: https:// threecats.com.au/ degoogled-pixelgrapheneos-userguide Fig.17: a screen grab of the Magic Earth mapping and navigation software. ● Iodé (https://iode.tech/iodeos-en) is a fork of LineageOS. It supports a variety of phones. ● LineageOS (https://lineageos.org) is based on Android and supports a large number of devices, not just phones; see https://wiki.lineageos. org/devices/ ● PureOS (https://pureos.net) is a version of Linux, not Android ● Sailfish OS (https://sailfishos.org) is Linux-based and has some closedsource, non-free components ● Silent OS (siliconchip.au/link/ abui) is an Android-based OS that appears to be for enterprise users, but we could find little information on it. ● Ubuntu Touch (https://ubuntutouch.io) is a mobile version of Linux. It supports various devices, including some phones – see https://ubports. com/nl/supported-products The following are not open-source nor free: ● Apostrophy OS (or AphyOS) is based on GrapheneOS; the only phone that uses it is the Punkt. ● CopperheadOS (https://copper head.co/android/) supports Google Pixel devices. Fig.13: the Punkt MP02 is similar to a dumb phone, but it can communicate with a portable computer and make encrypted VoIP voice calls via Signal. Fig.14: also from Punkt, the MC02 “smarter phone” is a smartphone that runs Apostrophy OS. siliconchip.com.au Australia's electronics magazine Using a de-Googled phone The phone service is not affected in a de-Googled phone but no Google apps will be provided. You will still be able to use Google search via a web browser, or you can use the alternative search engines mentioned earlier. To replace the missing Google apps, you can use: ● Newpipe (https://newpipe.net) is an open-source client that can be used to watch YouTube videos, although you cannot upload videos or comment on them. It also supports certain other streaming platforms ● K-9 Mail (https://k9mail.app) is an open-source email client that can read Gmail emails or other services. ● Nextcloud (https://nextcloud. com) is an open-source content collaboration platform that can be used as a substitute for Google Drive, Contacts, Calendar, Photos etc. ● Google Maps can be used in a browser window, but it does not work as well as the app. ● GmapsWV (siliconchip.au/link/ abuj) loads the Google Maps web page in a WebView and doesn’t need any Google services on your phone. ● OpenStreetMap (www.open streetmap.org) uses crowd-sourced maps stored in your phone. ● Organic Maps (https://organic maps.app) also uses OpenStreetMap maps. ● Another option for mapping is Magic Earth (see Fig.17). Gmail and YouTube can still be used via a browser without an app on a de-Googled phone, although some other apps no longer allow a browser option. Waze works on a de-Googled phone. App stores Google Play Store is not present on de-Googled phones but Android apps do not have to be downloaded from Google. Alternative app stores like June 2024  23  : the privacy phone that was a trap We covered this story in our December 2021 article on “Big Brother Is Tracking You!” (siliconchip.au/Series/373), but it’s so relevant that we thought we’d mention it again. In 2021, an international consortium of police, including the FBI, European police agencies and the Australian Federal Police (AFP), arrested over 800 criminals in 16 countries in a sting. They managed to sell them supposedly anonymised phones with the encrypted “Anom” app. The phones and app were specifically marketed toward criminals and only criminals could buy the phones and app which required approval from other criminals. Anom was like a criminal version of WhatsApp. The app was written by Australian police and the FBI, enabling police to monitor and target organised crime, drug trafficking and money laundering activities worldwide. The criminals did not know that every single one of their messages on the app was fed back to law enforcement officials. The FBI’s name for the operation was Operation Trojan Shield, while Australian law enforcement called it Special Operation Ironside. About 50 such phones were sold in Australia, and 224 people were arrested. For more on Anom, see siliconchip. au/link/abuv and siliconchip.au/link/abuw F-Droid host privacy-focused apps, although they only have about 4,000 apps compared to Google’s 3.5 million. Perhaps 90% of Google apps can still be installed on a de-Googled phone. The Aurora Store acts as a proxy for the Google Play Store and allows you to obtain certain apps without the Play Store. MicroG is an open-source implementation of various proprietary Google libraries that allows some Google apps to work on a de-Googled phone while maintaining privacy. Some apps (perhaps 10%) will not work because they rely on external “Firebase” Google services. Apps that require payment, like Uber, will not work, although bookings can be made via their website (https://m.uber.com). De-Googled phones are reported to have dramatically improved battery life (as much as double!) because the phone is not constantly waking up and uploading and downloading data to and from Google, Facebook etc. identification. They discard or destroy them after use. In Australia, there are identification requirements for buying a SIM card, but that doesn’t completely prevent misuse. Phone calls made and received, SMS texts and data usage are logged when a phone is connected to the network. The Australian government mandates that such ‘metadata’ records must be kept for at least two years (siliconchip. au/link/abuk). Call eavesdropping & spoofing Early mobile phones’ 2G and 3G connectivity to the PSTN relied upon a signalling protocol known as SS7 (see Fig.18), which was developed in 1975 and introduced in 1984. It was adopted as an international standard in 1988. SS7 implements call setup and routing, call forwarding, automated voicemail, call waiting, conference calling, caller ID subscriber authentication and extended billing, toll-free calls, premium charged calls, SMS, roaming and tracking. SS7 has an associated internet protocol suite called SIGTRAN (Signal Transport). SS7 has security weaknesses that allow: Attackers to interconnect with the network for surveillance, location tracking and interception of short messaging system (SMS) codes for two-factor authentication ... Voice calls can also be intercepted via SS7 attacks, which ... are tricky to block – siliconchip.au/link/abul SS7 is vulnerable because it is based on trust, not user authentication. Anyone with access to a server or gateway can send a location or redirect request to a telco, and if they believe it to be legitimate, they will follow it. It is said to be difficult to distinguish a legitimate request from a hostile one. 4G & 5G use an improved signalling protocol called Diameter (see Fig.19), built on SS7 but with enhanced protections. However, it is still considered vulnerable. Unlike SS7, it is purely IP (Internet Protocol) based. There is little a phone user can do to avoid their calls being intercepted by attacks via SS7 or Diameter. Even though 4G and 5G calls are encrypted by the phone, the encryption key can be intercepted by an SS7 attacker. SMS short messages are sent unencrypted. What privacy phones won’t do Each phone has a unique identifier linked to the account holder, and any phone connected to a cellular communications network can be tracked via mobile phone tower triangulation. The phone location can be established within about 150-300m in urban areas, regardless of what phone functions are used. Even turning the phone off might not keep you from being tracked! Criminals use ‘burner phones’ that were stolen or purchased with false Fig.18: the architecture of the SS7 mobile phone communications network. The database keeps track of mobile phones on the network. Original source: www.techtarget.com/searchnetworking/definition/Signaling-System-7 24 Australia's electronics magazine Silicon Chip siliconchip.com.au Fig.19: how the proposed trueCall CIV (Caller ID Verification) system integrates into the modern heterogeneous communications network. SIP (session initiation protocol) is for voice, video and messaging, while VoIP is voice over IP. Original source: www.researchgate.net/figure/CIV-for-heterogeneous-telecommunication-networks_ fig2_371506513 (CC-BY-4.0). The Pico Gamer A PicoMite powered ‘retro’ game console packed with nine games including three inspired by Pac-Man, Space Invaders and Tetris. With its inbuilt rechargeable battery and colour 3.2-inch LCD screen, it will keep you entertained for many hours. SC6912 | $125 + post | complete kit with white resin case shown* Other Items for this project SC6911 | $85 + post | complete kit without any case* SC6913 | $140 + post | complete kit with a dark grey resin case* * LiPo battery is not included SC6909 | $10 + post | Pico Gamer PCB* See the article in the April 2024 issue for more details: siliconchip.au/Article/16207 The only practical measure to avoid eavesdropping is to make encrypted VOIP calls or use an encrypted messaging app (see siliconchip.au/link/abum & siliconchip.au/link/abun). In Australia, it is illegal for government agencies to record your voice calls without a valid court order. However, Australia is a member of the “Five Eyes” (Australia, Canada, New Zealand, UK & USA) ECHELON program (see https://w.wiki/9qSX), which monitors voice calls, emails and internet traffic for specific keywords of interest to intelligence agencies. Caller ID spoofing Callers can fake the number they are calling from, making it seem like they come from a legitimate number like a bank. STIR/SHAKEN (https://w.wiki/9hz$) is a set of protocols intended to combat such spoofing. However, they only work with IP-based systems like SIP (VoIP) and cannot be scaled globally. CIV is an alternative proposed system that also protects SS7 and Diameter-­ c onnected phones (see Fig.19 & siliconchip.au/link/abuo). IMEI and IMSI numbers The IMEI (international mobile equipment identity) number is a unique identifier allocated to each phone and printed somewhere on the phone or displayed on the screen. It can be changed for legitimate reasons, although that is not legal in some jurisdictions, as the IMEI can be used to block stolen phones. Phones without physical SIM cards have an IMSI (international mobile subscriber identity) number that works similarly, although it can move between devices. The IMEI is not authenticated and can be spoofed by criminals to clone phones. It should therefore be kept confidential to prevent misuse. If selling a phone, it has been suggested to only give the buyer the IMEI number after purchase as criminals have masqueraded as buyers to get an IMEI number, after which the seller loses the ability to use the phone. mobile phone towers and trick phones within range to connect to them rather than legitimate towers. They can log the presence of people in certain areas by recording their phone IMSI number, call metadata, the content of SMS messages and voice calls and data usage such as websites visited. They are used by law enforcement agencies as well as some criminals. Hackers are known to have used a fake mobile phone tower to send an SMS to users with a link convincing them to download banking malware onto Android phones (see siliconchip. au/link/abup). Tracking a powered-off phone Firstly, when a phone is “off”, the baseband processor (inside the radio chip) may still be active. It draws very little power in listening mode and can be remotely commanded to wake up the phone and do other things; in some cases, it can even enable the microphone! Then there is ultra-wideband (UWB) tracking. UWB is a low-energy, shortrange, high-bandwidth radio technology that can be used for precise device location. Radio signals are generated as pulses sent over a wide bandwidth at specific time shifts compared to a clock signal, with the time shift encoding information according to a predetermined coding scheme. The high bandwidth (>500MHz) allows the transmission of a large amount of energy while keeping within the regulatory limits of output power. The modulation technique is known as pulse position modulation (PPM), with clock-independent variations, such as differential pulse position modulation (DPPM; see Fig.20). This is in contrast to conventional digital radio, where the frequency, phase or a combination of both are varied over a small bandwidth to transmit information. UWB uses several techniques to establish location, such as time-offlight, time difference of arrival and two-way ranging. We will cover these in more detail in a later article. Phones and devices with a UWB chip include iPhones since the 11, Apple Watch since Series 6, Apple AirTags, Samsung Note 20 Ultra, Galaxy S21+, Galaxy S21 Ultra, Galaxy SmarTag+ and Xiaomi MIX 4. Chips in these devices can precisely locate other devices at short distances. The accuracy is around 10-50cm at a range of up to 200m using frequencies of 3.1-10.6GHz and data rates up to 27Mbps (see siliconchip.au/link/ abuq). The FiRa Consortium (www. firaconsortium.org) promotes interoperability of Ultra Wideband devices. Apple devices use the U1 ultra-wideband chip that is always powered even when the phone is ‘off’, as long as the battery is not completely flat. Incidentally, UWB technology is used in the US NFL football league to track the movement of players on SC the field. Fake mobile phone towers The Stingray was a product of Harris Corporation (now L3Harris Technologies) that has become a generic term. It refers to devices, also known as IMSI catchers, that masquerade as 26 Silicon Chip Fig.20: the Pulse Position Modulation (PPM) scheme. A clock-independent variation is Differential PPM or D-PPM. Original source: www.pcbheaven.com/ wikipages/Pulse_Position_Modulation/ Australia's electronics magazine siliconchip.com.au