4. Private Messaging with Signal Messenger
How to maintain data security while messaging online, installing and using Signal Messenger, secure messaging platform.
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How to maintain data security while messaging online, installing and using Signal Messenger, secure messaging platform.
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Learning objective: Establish a secure messaging platform to transmit sensitive private, personal or commercial information.
Signal Messenger, from Open Whisper Systems (supported by grants and donations), is an open-source instant messaging platform that offers best-in-class encrypted messaging and is one of the most robust and simplified messaging solutions available at present. It uses the Internet to send one-to-one and group messages which can include files, voice notes, images and videos, and supports one-to-one voice and video calls. Similar in its functionality to WhatsApp – which licenses from the Signal developers the underlying technology known as Open Whisper Systems – Signal is a superior solution for everyday private messaging and one of the best places to start your privacy journey. Its one of the quickest and easiest ways to start down the path of secure messaging and is the messaging platform of choice for many journalists, politicians and business people who require security for the messages they send and receive.
Ok, So what makes Signal so great and why is it different from other messaging platforms? First, all communications to other Signal users are end-to-end encrypted. Additionally, the “keys” that are used to encrypt the user's communications are generated and stored on the user’s device, not on the providers servers. And Signal also has built-in mechanisms for verifying that your private communications are integral. If the integrity is lost, you will be advised. For authentication, Signal users can compare key fingerprints (or scan QR codes). All told, it is the most comprehensively secure app available today. All others, including FB Messenger, WhatsApp, Viber, Line, Telegram and Threema, fall way short of offering the transparency and horsepower of Signal.
One criticism of Signal is that it requires SMS verification and therefore a mobile phone number. This goes to the ‘linking’ issue we talked about in Module 1, so you may want to make sure that you have already been through the steps there to establish a ‘private’ phone number that you can use for Signal’s two-factor authentication.
Again, bear in mind that if you want to use a one time, pre-paid SMS number, VoIP or other service to create your Signal account, it’s important to keep that number registered. If you don’t and that phone number goes back into “the pool”, anybody else who has access to that number and its online SMS system in the future will be able to kick you out of your Signal account, since only one mobile device can be linked to a Signal account at a time.
It is also worth noting that if you change your device you will need to re-authorise the phone number on the new device. This is because the app employs a “trust on first use” mechanism – automatically notifying you if correspondent's key changes or alerting them if yours changes. When your “security number” changes, you will not have access to your old messages on your new device, or new messages on your old device. You’ll need to advise your correspondents that the change in security number was your doing – otherwise they may reasonably assume that someone else has control of your Signal account; and you will want to check with others when their number changes to see it was their doing before sending any further private correspondence.
OK, so let’s dive in now to help you get going with your very own Signal Messenger account. For the sake of this tutorial, we are going to assume that you have already taken care of getting a secondary phone number. Again, a secondary unregistered SIM card may be the easiest and best way to get going. First, we are going to get you going with Signal on your smartphone device. After that we will connect that device to the Signal Messenger for Desktop so you can message over Signal from your computer.
From , download and install the Signal Messenger App on your Smartphone. Alternatively, you can search for it as Signal Messenger in iTunes or Google Play.
Once Signal is installed, launch it and add and verify your phone number by SMS.
You can add profile data or skip this step entirely.
Allow Signal to access your contacts and allow notifications.
Go to on your computer and download the appropriate version for that machine.
Once it’s downloaded, run the installer. Note: if you are a Mac user, you may need to bypass Mac Security. Ask your trainer how.
Once Signal has finished installing, follow the prompts to sync your desktop version of Signal with your mobile device.
Now you are good to go with messaging anyone you know, privately and securely, via Signal Messenger. Congratulations and welcome to the world of private messaging!