Chapter 7: Phones & Voice/Video Calls Over Internet

Mobile security

Many of us find our smart phones to be of great importance and value in our everyday lives and work. The benefits of being constantly connected to our email accounts, web browsers, social media, calendars, and also having easy access to a high quality camera and voice recorder, do indeed make them valuable tools. However, they are not feasibly securable tools.

An alternative is to use burner phones, with diligence and caution – but even this has its risks.

Phone risks:

  • Automatic logging of your current/past locations
  • Automatic collection of metadata, ie the phone number and location of every caller; unique serial numbers of phones involved; time and duration of call; telephone calling card numbers
  • Theft and loss of data
  • Remotely accessing data when phone connects to public wi-fi
  • Remotely accessing all data at any point the phone is on
  • Phone/voicemail tapping, intercepting, or recording
  • Covert remote automation of microphone to record audio
  • Covert remote automation of camera to capture images

Dragnet phone surveillance

All phones leak an enormous amount of information about us to intelligence agencies, and we know from the Snowden revelations that programs collecting the full audio of every single call within a nation are, at the very least, already being trialled in some countries. This type of surveillance is extremely dangerous for democracy, let alone journalism, and may permit the most invasive ‘retroactive’ investigation of individuals who become of interest to intelligence agencies at some point in the future.

Therefore, it is worth using any phone with this in mind, whether you, your sources or colleagues may be targets of intelligence agencies now, or years in the future. They are not secure communication devices, so consider carefully how you want to use them.

Targeted phone surveillance

Low risk

At a low risk level, the threat is mainly physical – someone gaining access to the handset. If this happens, even a fairly unsophisticated hacker/the police can normally crack your password (if you use a password lock) so this only provides minimal protection. If you are at a low risk level, be sure to back up your data and stream or send any video or audio being recorded on the device to a secure storage cloud as soon as possible.

You can also use applications to track your device, should it be stolen. For iPhone, for instance, Apple offer a free app called ‘Find my iPhone’ which tells you the current location of your phone. Another free anti-theft app is ‘Prey’ which, once you report the phone as stolen, will record not only the current location of the phone, but any other locations of the phone registered since you reported it stolen.

Medium risk

At a medium risk level, you may encounter an adversary trying to gain access to your data, not just physically, but remotely. When you connect a phone to a public wi-fi connection, for example, a fairly unsophisticated hacker can intercept lots of information about you and connected accounts such as email and social media. Therefore, at a medium risk level, you may already be thinking about avoiding a smart phone as a work tool, or at least guarding it closely, closing applications after use, turning off wi-fi in public, and using flight mode when you don’t need to be connected.

  • A note about smart phones: the vulnerabilities of smart phones are numerous, with some existing in the hardware, and they are not fixable. You can use open source software on smart phones, and even applications for encrypted chat (e.g. Signal). However, as we discovered in ‘Protecting the System’, when hardware is vulnerable, the software cannot provide you with real security. Therefore, we will not discuss such apps for the purpose of this guide.

As the recent phone hacking scandal in the UK demonstrated, unsophisticated hackers working for unethical journalists were able to listen in on people’s voicemail. Private investigators often also have the ability to ‘phone tap’ (i.e. eavesdrop) not only voicemail but general phone calls made and received by a number. Therefore, you should think before you discuss anything sensitive on your (mobile or indeed landline) phone.

High risk

At a high risk level, a phone basically is your adversary. At the very least, it logs your location, and all associated metadata with the device is in the hands of a Five Eyes intelligence agency. At worst, it can be exploited to covertly collect the content of all of your phone calls, let alone all other data on the phone, and to covertly automate your microphone and camera to record audio and images (if it has a camera) too. This type of phone surveillance is very easy and basically comes at zero-cost to Five Eyes intelligence agencies.

An alternative way of using phone communications is to use burner phones.

Ideally, your burner phone and regular phone will never both be emitting signals, since (if you are a target), your regular phone may pick up on the signal of the burner phone, making that a target too.

Before you use a burner, make sure the phone usually associated with you (e.g. your smart phone) is not emitting signals. Switching the phone to flight mode, removing the battery (don’t bother trying to do this to the iPhone), and turning it off is good but is not enough. Do all of these things and then put it in a Faraday cage – popular solutions are biscuit tins, some fridges, or even a stainless steel cocktail shaker! The phone has to be completely sealed in metal (check it is working by trying to call the phone). It is a good idea to find and carry a small tin around with you to put your phone in, and in an important meeting, make sure all attending have done the same (a larger biscuit tin works well here).

A burner phone is a cheap, cash-bought, throwaway, low-tech phone, with a prepaid SIM card not registered to you, to be used only for specific purposes. It can be hard, in some countries, to buy a SIM card without registering it with your personal details. Therefore, buying second-hand, or having a contact that can obtain such SIM cards, is ideal.

After some use of the phone, the phone may become associated with you and attract surveillance, at which point you should destroy it and use a new one. Changing the SIM card is not enough – each phone handset also has an IMEI (International Mobile Equipment Identity) number that identifies the phone. If the SIM has been identified as being yours, the IMEI will be too – so you will need to destroy the phone.

Due to intelligence agencies rolling out full audio recording of all phone calls, let alone the ease with which they can record a target’s phone calls, you should avoid sharing particularly sensitive information - even on a burner phone.

Warning: intelligence agencies are increasingly developing methods to identify use of burner phones, by scanning bulk communications data patterns for anomalies. It is thought that they similarly surveil use of public phone booths. Therefore, one should conduct a risk assessment before using burner phones to communicate with a high-risk source.

Internet voice and video calling

Software that provides voice and video calling over the internet (Voice over Internet Protocol, VoIP), such as Skype, is enormously popular and useful, with Skype having over 700 million users itself. However, Skype does not offer much security, and there is not yet any user-friendly, secure alternative.

Among the Snowden revelations are details of the NSA’s ability to intercept and store Skype communications. We should assume that all Skype communications are not just between us and our contacts, but with intelligence agencies too.

Example: Glenn Greenwald tells a story of when he used Skype in Hong Kong to call his partner back in Rio, David Miranda, to tell him he would receive some encrypted documents by email, and to store them securely. Greenwald never did send those files – but 48 hours later, Miranda’s laptop was stolen from their Rio home.

We should also assume that it is not only the most sophisticated agencies that have covert access, or who have exploited security flaws. For example, Egypt’s secret police are known to have purchased Skype penetration tools, and man-in-the-middle Skype attacks have been reported by environmental campaigners working in Asia.

Secure internet voice and video calling is being developed – current projects in development include Jitsi (see and Tox (see  Whilst these projects are encouraging, they are still in development and so it may be too soon to assert what degree of security they can offer or how user-friendly they are.

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