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Instant Messaging on Smart Phones

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If you work with sensitive information and topics, and are interested in using social networking services, it is important to be very aware of the privacy and security issues that they raise.
Anyone needs to be vigilant about their use of social networking sites and need to be careful about the information they reveal about themselves and about the people they work with.

Instant messaging on phones

Learn to instant message securely on a smart phone.

Scenario

Mansour and Magda are human rights defenders from Africa. They are organising a march, to take place in the middle of a large city. They want to use Facebook to publicise the event. They are worried that the authorities could be tipped off and that anyone who shows an interest in attending the event could be traced.
They plan to use Twitter during the march to give updates on the progress of the march. But what if the police could monitor the tweets, and deploy squads to intercept marchers? Mansour and Magda plan how to share photos and videos of the march without revealing people's identities, because they worry that participants could face persecution.

Scenario

Mansour and Magda are journalists from north Africa. They are covering a march, to take place in the middle of a large city. They want to use Facebook to publicise the event. They are worried that the authorities could be tipped off and that anyone who shows an interest could be traced.
They plan to use Twitter during the march to give updates on the progress of the march. But what if the police could monitor the tweets, and deploy squads to intercept marchers? Mansour and Magda plan how to share photos and videos of the march without revealing people's identities, because they worry that participants could face persecution.

Scenario

Mansour and Magda are from north Africa. They are going to a march, to take place in the middle of a large city. They want to use Facebook to publicise the event. They are worried that the authorities could be tipped off and that anyone who shows an interest could be traced.
They plan to use Twitter during the march to give updates on the progress of the march. But what if the police could monitor the tweets, and deploy squads to intercept marchers? Mansour and Magda plan how to share photos and videos of the march without revealing people's identities, because they worry that participants could face persecution.

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How-to

This how to will go through the following steps

  • (1) How to Install Signal
  • (2) Registering with Signal
  • (3) Configuring Signal

(1) How To Install Signal

  • Download from the Playstore
  • Review the permissions
  • Launch the Signal app

Step 1. On your Android device, download and install the app from the Google Play store by tapping

Figure 1: Signal on the Google Play Store

Step 2:. Before the installation process begins, you will be asked to review the access that the app will have on your phone. Review this carefully. Once your are happy with the permissions allowed, press and the installation will complete. If you do not agree with the permissions allowed, press the back button and the installation will be cancelled.

Figure 2: Permissions required

Step 3. Tap Open to run the app for the first time

(2) Registering with Signal

  • Enter your phone number
  • Receive an SMS.

Step 1: Begin the registration process by entering your phone number including country code and press

Figure 3 & 4: Registration screen and confirming number

Step 2: Signal will send you an SMS message to confirm registration.

Note: If for some reason you do not receive the SMS you will be given the option to receive an automated phone call where you will hear a 6-digit code, this code once entered will complete the registration.

Figure 5 & 6: Registration completing and Voice verification screens

(3) Configuring Signal

  • Importing Messages
  • Making Signal the Default Message App
  • Encrypted Storage

Importing Messages

As Signal can securely store your SMS messages, so it is recommended that you import the messages from your current SMS app.

Step 1: After registration is complete, Signal will open and you will be asked if you want to import your messages from the default SMS app on your phone. Press

Figure 7: Import messages into Signal

Once the import is complete you can access all your old messages in Signal and you should delete them from your other application.

Making Signal the Default Message App

After your old messages have been imported you should make Signal the default SMS application so that all messages you receive appear in it and not the old application. This can be done by tapping when prompted.

Figure 8: Set Signal as the default SMS application

Encrypted Storage

Signal also allows you to store all your messages in an encrypted container protected by a passphrase, so if someone gains access to your phone, they will not be able to access your messages when Signal is locked. After a set period of time, if you have not looked at any messages, Signal will automatically lock and you will have to enter your passphrase the next time you want to read your messages.

Step 1: Tap on in the top right of your screen to bring up the menu and select .

Step 2: Scroll down to the PASSPHRASE section and uncheck Disable Password.

Step 3: When prompted enter a passphrase that will be used to protect the messages stored on your phone and tap .

Figure 9 & 10: passphrase options and setting a password

Step 4: Check the box next to Timeout passphrase to have Signal lock after a period of inactivity (See Fig 9 above).

Step 5: Tap Timeout interval and in the next screen enter after what time you want Signal to lock if unused and tap .

Figure 11: Signal timeout settings

How-to

Below are the steps that you will take to send and receive encrypted text using Signal:

  • Sending and Receiving messages
  • Messaging Individuals
  • Messaging Groups
  • Identity Verification
  • Reading Fingerprints
  • Scanning Fingerprints
  • Export your messages

[1] Sending and Receiving messages

Note: To send encrypted messages to your contacts, they must also have Signal installed, otherwise the message will be sent as an insecure SMS.

Signal can send messages as SMS using your mobile phone company to relay the message. With this option, even if your recipient is using Signal and the SMS is encrypted, your mobile phone company will know that you are sending a (encrypted) message to this particular recipient.

If your phone is connected to the Internet, either using a data connection offered by your mobile phone company or using local wifi, Signal will instead send the message over an encrypted connection with a WhisperSync server. In this instance, your mobile phone company will not know who you are sending your messages to.

[2] Messaging Individuals

Step 1: Open Signal and tap at the top of your screen to bring up your contact list.

Step 2: Tap on the contact you wish to message.

Note: The contact list will display at the top all your contacts who also use Signal (under the Signal Users heading) and then your full contact list (including Signal users) in the All Contacts section.

12.png Figure 1: Signal contact list

Step 3: Compose your message in the box and tap to send.

Note If you send a message to another Signal user and you are connected to the Internet, the default option is to send it via Internet. If you want to send an encrypted SMS (using your mobile phone company) or an insecure SMS instead of an encrypted message long press to bring up the alternative sending options.

2s.png
Figure: 2s.png

3s.png Figure 2 & 3: Sent message / Alternative sending options

Things You Should Know

Your sent messages are given different background colours / indicators to help you identify how they were sent:

Blue with a icon: The message was sent encrypted via Internet.

4s.png Figure 4: Encrypted message send via mobile data

Green with a icon: The message was sent as an encrypted SMS.

5s.png Figure 5: Encrypted SMS

Green: The message was sent as an insecure SMS.

6s.png Figure 6: Insecure SMS

A icon in your message indicates that it has been delivered. Note: the only appears by default when messages are sent via Internet; to see them when sending SMS you need to enable SMS delivery report in settings.

The messages you receive from your contact will always be grey. If they have a icon, they were received encrypted. If there is no icon the message was received insecurely.

[3] Messaging Groups

Signal also allows you to message multiple people at once.

Note: If at least one of the people you are messaging does not use Signal, the messages will be sent as an MMS and not encrypted.

Step 1: Tap on in the top right of your screen to bring up the menu and select

Step 2: Enter a name for your chat group and tap to add your contacts.

Step 3: Tap the box to the right of each contacts name to add them to the group and press.

7s.png
Figure: 7s.png

8s.png Figure 7 & 8: Contact selection & Group Creation

Step 4: Tap to complete the creation of the group and be brought back to the Signal main screen.

Step 5: Tap on the group you have created and begin messaging the group.

9s.png Figure 9: Group conversation

[4] Sending Files

Signal allows you to send images, video and audio files to your contact.

Step 1: Start a conversation with the person you want to send the file to.

Step 2: Tap on in the top right of your screen to bring up the menu and select .

Step 3: Choose from the list the type of file that you want to send - Picture / Video / Audio

Step 4: Select the file you want to send.

Step 5: Verify that the file you want to send is in the compose window and press to send.

10s.png
Figure: 10s.png

11s.png Figure 10 & 11: File type selection / Image sent to contact

[5] Identity Verification

To confirm that the messages you are sending and receiving are with the right person, you should both verify your Signal identities with each other.

[6] Reading Fingerprints

The Following steps will need to be performed by both parties.

Step 1: Open an existing conversation with your contact and tap at the top of the screen.

Step 2: Tap from the pull-down menu.

Step 3:You will be presented with a 66-character fingerprint of your Signal identity and that of your contacts. These should be read to each other, and verify that you both have the same fingerprints for each other, either in person or via a medium that allows you to confirm visually or audibly to whom you are talking.

13s.png Figure 12: Signal fingerprints

[7] Scanning Fingerprints

Note: To verify fingerprints by scanning you need to have Barcode Scanner installed on your phone. If it is not available on your phone at the time of scanning Signal will download and install the app for you.

The Following steps will need to be performed by both parties.

Step 1: Open an existing conversation with your contact and tap at the top of the screen.

Step 2: Tap from the pull-down menu.

Step 3: You will be presented with a 66-character fingerprint of your Signal identity and that of your contacts.

Step 4: On both your phones tap on .

Step 5: On your phone tap and your contact should tap . Your contact's phone will display a QR code and your phone will open Barcode Scanner.

Step 6: Use Barcode Scanner on your phone to scan your contact's QR code.

14s.png
Figure: 14s.png

15s.png Figure 13 & 14: Your contact's QR code / Barcode scanner

Step 7: Once the QR code has been successfully scanned Signal will check that the identity is valid.

16s.png Figure 15: Signal identity verified

Step 8: Once you have verified your contact's Signal identity, they should repeat the above steps to verify yours.

[8] Export your messages

Note: While Signal allows you to export your messages, the messages in the backup file will not be encrypted and you should take additional steps to protect its contents.

Step 1: Tap on in the top right of the main Signal screen to bring up the menu and select .

Step 2: The next screen will open on the import options, tap .

Step 3: On the export screen tap .

Step 4: Confirm that you want to export the unencrypted messages to the storage on your phone by tapping .

Step 5: Signal will confirm the export has completed by displaying . You will find a file called Textsecure.xml on your phone's storage that contains your unencrypted messages.

17s.png
Figure: 17s.png

18s.png Figure 16 & 17: Signal Export and Export confirmation screens

How-to

Make a call

Tap on a contact. If they have Signal there will be a padlock on the top right of the screen.

Call your contact. When your contact answers you'll see two words. Say one word to your friend and ask them to say the other word. This makes sure you are both who you say you are.

10s.png
Figure: 10s.png

Take a call

When you get a signal call, you'll see on your screen "SIGNAL CALL"

When you answer you'll see two words. Say one word to your friend and ask them to say the other world. This makes sure you are both who you say you are.

11s.png
Figure: 11s.png

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