Another secure messenger that promises all kinds of encryption methods and a complete lack of monetization. The idea and implementation is very similar to the well-known Telegram.

Immediately after installing the application, a misunderstanding may arise, since the Signal Private Messenger does not appear in the list of programs, but the TextSecure shortcut appears. It turns out that Signal Private Messenger is a service, but TextSecure is a shell for it. Why did the developers do this? It's hard to say, but there were clearly reasons for that.

The registration procedure for the service is the same as for all similar messengers - through the verification of the phone number. After a short wait and the receipt of an SMS with a code, registration will be completed automatically. Next, we are thrown to the main screen with the started chats. By clicking on the pencil in the lower left corner, you can instantly see which of your contacts are using Signal Private Messenger. All conversations immediately become encrypted and not even the developers have access to them. In case of doubt, you can always check your personal fingerprint for identity.

The settings of the program have not yet been overgrown with functionality and are a cropped copy of Viber, Telegram and others. But already now there is such a tab as Confidentiality, where you can screw up the program and set up automatic deletion of old messages, as well as prohibit screenshots from chats.

From the program you can send SMS to your contacts and make calls. That is, TextSecure to some extent replaces the standard phone application. Signal Private Messenger is a good alternative to the more famous secure messengers.

Features::

• You can say whatever you want without fear because Signal messenger uses an advanced encryption protocol from one user to another.
• Open resource. Verification by code. Cryptographic protocols are responsible for security.
• Be yourself - Signal uses your existing number and address book. No separate logins, passwords.
• Group chat. In Secret Groups, you can chat and discuss important issues. Not only messages will be encrypted, but also the list of participants.
• Fast work. The messenger protocol is designed in such a way that messages will instantly reach the address.
• High quality communication - even if the ocean separates you, you will hear everything.

Download application for confidential calls and messages - Signal Private Messenger for Android you can follow the link below.

Messenger Signal for Android is a convenient application for communicating with high data security. It has an extremely simple interface consisting of one tab, a settings window and several pop-up menus. Let's consider the procedure for its installation and the nuances of the first launch.

Installation

There are two convenient ways to install applications on Android mobile devices. The first is considered the most convenient. It consists in downloading Signal from the Play Market software store. The messenger is completely free there. An alternative is to install from an apk file.

At the moment, the messenger is still in development, and only the beta version is available to users. This means that certain problems may occur in its operation.

Option 1: Play Market

Play Market is a software store that has been verified by Google. Typically, users download applications from there. And this is the preferred installation option. Follow this procedure.

If you try to open the Signal page inGoogle Play on the tablet, an incompatibility error will be displayed. It will not be possible to install the application in this way, use an alternative one.

Option 2: apk file

If you download the apk file of Signal Messenger Private, then it can be installed on any device running Android, bypassing the official method through the software store. This option will be useful in several situations:

• Installing the service on a tablet. The developers only officially support smartphones, so the first method simply won't work.
• Limited internet. The size of the app is 31 MB. For some tariff options you will have to pay for such traffic consumption. In this case, it is much wiser to download the apk from the computer, and then transfer it to the gadget's memory.
• Lack of Google services on the device. Smartphones not released for the international market often lack built-in support for Google applications, including the Play Market. Then installation via file is the only available method.

Installation instructions:

Signal Private Messenger allows you to achieve privacy while communicating using a mobile device.

Using Signal, you can chat instantly, avoiding SMS / MMS messaging fees. Create groups and you can chat with several friends in real time and exchange media files and attachments with maximum privacy. The server never has access to your connections, and it never stores any of your data.

Key features of Signal Private Messenger

• Say what you want: Signal uses an advanced encryption protocol to ensure the privacy of your communications.
• Open Source: Signal is free and open source, any qualified user can analyze the application code. Signal is the only messenger that uses open cryptographic protocols for secure message transfer.
• Be yourself: Signal uses your real phone number and your address book. The application does not use separate logins, passwords or PINs for authorization.
• Group Chat: Signal allows you to create encrypted groups for private communication with multiple contacts at once. Security is achieved not only due to encryption of messages, but also due to the fact that the server does not get access to the transmitted data, as well as to the list of participants, the group name and the group icon.
• High speed: Signal protocol is designed with maximum optimization. Messages in Signal are sent to recipients instantly.
• Talk freely: make quality phone calls to neighbors and friends overseas without paying for distance.

Signal for Android is not currently compatible with tablets, but support for large screens is in development and will be available in a future release.

• How to exchange encrypted messages with other Signal users.
• How to make encrypted calls to other Signal users.
• How to encrypt messages on a smartphone using a password.

1. Getting to know Signal

Remember, that:

• Signal only encrypts messages that you exchange (over mobile or wi-fi) with other Signal users. The Android version also knows how to send and receive SMS text messages, but does not encrypt them.
• Although Signal prevents unauthorized access to the content of messages and audio communication, the application cannot hide the fact that encrypted messages are sent or calls are made.
• To register Signal, you need to receive an SMS or take a phone call from the United States.
• Signal can only be installed from the Google Play store, which means you need a Google account; it must be specified during installation.
• Signal works with Google Cloud Messaging mobile service so that Google can access some Signal metadata (for example, the IP address of the device that receives the Signal message).
• In some countries, encryption tools like Signal can break laws and attract outside attention.

Note. If you want to use the Signal protocol for encrypted mobile communications independently of Google Play, you can install the LibreSignal app (Signal version) from the open source Android F-Droid archive.

1.0. Signal analogs

• Android: Surespot, ChatSecure, Silent Circle, Conversations, OSTel.
• iOS: Surespot, ChatSecure, Silent Circle, OSTel.

2. Installing and configuring Signal

2.1. Installing Signal

To install Signal on your Android device, follow the steps:

Step 1. Download and install Signal from Google Play - click the button.

Figure 1. Signal on Google Play

Step 2. Before starting the installation, you will be presented with a list of permissions that Signal asks for. Pay attention to this list. If everything suits you, click the button and the installation will be completed. If you do not agree with the permissions, press the "reverse" button and the installation will be canceled.

Image 2. Permissions

Step 3. Click on button Opento open the app.

Figure 3. Opening Signal

2.2. Initial settings

2.2.1. Signal registration

To register Signal, you will need to receive an SMS or voice call from the United States.

Here's how registration works:

Step 1. First enter your mobile phone number including country code and click Register now.

Figure 1. Registration window

Step 2. Signal will send an SMS to confirm registration.

Note. If for some reason you have not received the SMS, there is an option with an answering machine. Call and you will be given a six-digit code. Enter the code to complete registration.

Image 2. Registration completed

2.2.2. How to make Signal the default text messaging device

So, Signal provides the exchange of encrypted messages between users. Additionally, the Android version of Signal can be installed as a replacement for your regular SMS app. Then Signal will be able to send messages unencrypted to those who do not have Signal, and receive messages from them (via mobile operators, not over the Internet).

To use Signal as your default SMS application, note the following feature:

Figure 1. Signal suggests replacing your default SMS app

Step 1. Click by the mentioned window.

Figure 2. Confirming Signal as an SMS app

Step 2. Click on YES.

2.2.3. Import messages

If you are setting up Signal as an SMS messaging application, we recommend importing existing messages. This way all your messages will be stored in one place. Since Signal is able to encrypt messages on the device, the history of your SMS messages will be protected. This will come in handy if someone gains access to the device.

To complete this setup, follow the steps:

Step 1. After registration is complete, when the Signal application itself opens, you will be asked to import your messages from the default SMS application. Click on the message to agree.

Figure 1. Importing messages into Signal

When the import is complete, your old messages will be available through Signal. You should remove their old copies from the default application.

2.2.4. Using encrypted storage

Signal also allows you to store all messages in an encrypted container that is password protected. If someone gets to your smartphone, they cannot access your messages - provided Signal is blocked. This blocking turns on automatically if you have not viewed any messages for some time. After activating the lock, you need to enter a password to access messages.

To store messages in an encrypted container, you need to do the following:

Step 1. Click on the icon in the upper right corner of the screen to bring up the menu. Select item Settings.

Step 2. Scroll down to section Confidentiality... Enable the option "Include passphrase".

Figure 1. Password option

Step 3. Enter password to protect messages on your phone and click OK.

Figure 2. Setting the password

Step 4. Check the item Passphrase on inactivityto set Signal to lock after a period of inactivity.

Figure 3. Period of inactivity

Step 5. Select item Inactivity interval... A screen appears to select the time after which Signal will lock. Click on OK.

Figure 4. Timeout settings in Signal

2.3. Invite people to Signal

You can invite people from your contact list to use Signal. Follow the steps:

Step 1. Start Signal.

Step 2. In the main window, click on pencil icon in the lower right corner. A list of contacts will open.

Step 3. Select the contact you want to invite to Signal.

Step 4. Click on the blue box Invite to Signal.

Figure 3. Invite friends to Signal

Step 5. Click on the send icon in the lower right corner of the screen. A message will be sent to the selected person "Let's communicate through Signal".

Figure 4. Go to Signal

When your contact connects to Signal, you will receive a notification:

Figure 5. The interlocutor joined Signal

In the future, you can determine which of your interlocutors uses Signal by the presence / absence of a lock icon next to the phone icon next to the name:

Figure 6. A padlock icon confirms the use of Signal

3. Encrypting messages using Signal

Signal encrypts messages only for those of your interlocutors who also use Signal. For encryption, you need to turn on the data transmission mode of the mobile operator or access the Internet via wi-fi. The Android version of Signal allows you to send and receive regular SMS messages, but they will not be encrypted. As a result, your mobile operator will have the fundamental ability to access the content of messages.

End-to-end encryption is used when you send a message via Signal and the other person receives it via Signal. No one other than the sender and the recipient can read message. Even a mobile operator. Even the developer of the program is Open Whisper Systems. Even Google. This applies not only to text, but also to photos, videos and other attachments.

Although the Signal protocol implies encryption of the content of communications, metadata are not encrypted. ( Metadata - information about message, for example, the address / phone of the sender, when and from where the message was sent). The fact that Signal uses the Google Cloud Messaging platform means that Google may have access to some Signal metadata, in particular to IP addresses any devices that receive Signal messages.

3.1. Sending messages to individual users

To practice sending encrypted Signal messages to your friends, follow these steps:

Step 1. Open Signal and click on pencil icon in the lower right corner of the screen. A list of contacts will appear.

Figure 1. Signal main window

Step 2. Click on the contact you want to contact.

Figure 2. Selecting a contact in Signal

Step 3. Compose your message and click the icon to send.

Figure 3. Sending a message using Signal

The Android version of Signal allows you to choose how to send a message: encrypted via Signal or as usual insecure SMS... To assign this or that option to a specific interlocutor, press and hold send message icon. Signal will remember the settings. If you later want to change your mind, again press and hold this icon.

Figure 4. Options for sending a message

Important. The closed lock icon under the message (as in the picture below) indicates that it was sent encrypted. If the icon is shown open, the message was not encrypted. In addition, if next to the lock you only see one a check mark means that the message has only been delivered to the server. If there two check marks (as in the picture below), it means that the message was delivered to the addressee (although it is impossible to determine whether it was read or not)

Figure 5. Exchange of encrypted messages

3.2. Sending messages to groups

Signal also allows you to send encrypted messages to multiple recipients at once. True, if at least one of them not uses SignalMMS messages sent not will be encrypted.

To send a message to multiple recipients, follow the steps:

Step 1. Click the icon in the upper right corner of the screen and select from the menu A new group.

Figure 1. Selecting a new Signal group

Step 2. Enter the name of your chat group and click to add contacts.

Figure 2. Adding members to a chat group in Signal

Step 3. Check the box to the right of each contact to add it to the group and click the checkmark icon.

Step 4. Click the checkmark in the upper right to complete the group creation and return to the main window Signal.

Step 5. Select the group you created and compose a message for it.

Figure 3. Sending encrypted messages to multiple recipients at once

Figure 4. Sending messages to multiple recipients using Signal

3.3. File upload

Signal allows you to send messages, videos and audio files to your recipients.

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

Step 2. Click the icon in the upper right corner and select from the menu Add attachment.

Figure 1. Attaching a file

Step 3. Select the type of file you want to send.

Figure 2. Selecting the file type

Step 4. Make sure the file you selected is in the compose window and click.

Image 3. Image sent via Signal

3.4. Identity verification

How can you make sure that you are really exchanging encrypted messages with your interlocutor and not with someone else?

When you first connect with someone through Signal, the program creates a unique set of numbers. Signal calls them safety numbers (safety numbers)... These numbers must match exactly on your phone and on the phone of your interlocutor. If the numbers do not match, it is possible that one of you changed your phone and reinstalled Signal. Or maybe it is an intruder who pretends to be you or your interlocutor. If the deception succeeds, the attacker will be able to record your messages / statements, decipher them, and generally do anything with them. It is called man-in-the-middle attack... This is why it is so important to make sure from the outset that safety numbers on your devices are the same.

Important. If an intruder gets hold of your (not locked) smartphone, he can, among other things, use Signal, pretending to be you (at least for some time). Protect your smartphone, for example, with device encryption and a strong password.

To check safety numbers, you and your interlocutor should do the following steps:

Step 1. Open a chat with your interlocutor. Click on the icon in the upper right corner of the screen and select Conversation settings.

Figure 1. Conversation settings in Signal

Step 2. Select in the "Conversation settings" item Verify safety numbers.

Figure 2. Checking the "safety numbers"

Step 3. You will see a QR code and a set of numbers right below it. You and your interlocutor should compare these numbers: they must match on your devices. For verification, a face-to-face meeting would be best, but if this is difficult, another means of communication is suitable, where you can visually or by sound identify the speaker.

Image 3. "QR code and security numbers"

An alternative to reading "safety numbers" to each other is scanning QR codes... This is a faster and cleaner way. It is convenient if there is a possibility of a personal meeting. One of the interlocutors clicks on the image of the QR code on his phone. Appears code scanner... It needs to be hovered over the QR code displayed on the interlocutor's phone. If everything is ok, Signal will show a green circle.

Figure 4. Verification was successful

3.5. Export messages

Signal allows you to export messages. True, this backup not will be encrypted. Therefore, you need to take additional protective measures.

Step 1. Click in the upper right corner of the main Signal window. A menu will appear, select Import Export.

Figure 1. Import / Export in Signal Menu

Step 2. Items concerning data import... Please select Export.

Figure 2. Import / Export Settings

Step 3. On the screen export click Exporting a simple backup.

Figure 3. Export backup

Step 4. Confirm that you want to export unencrypted messages. To do this, click EXPORT.

Figure 4. Confirmation of backup export

Step 5. Signal will confirm that the export is complete: you will see a message Exported successfully... You now have a file in your smartphone that contains your not encrypted messages.

4. Encrypting voice calls using Signal

4.1. Phone call encryption

So, you have installed and configured Signal, invited friends to join, now you can do encrypted calls.

Step 1. Open Signal.

Figure 1. Signal main window

Step 2. Click on the contact - the person you are going to call.

Figure 2. Selecting a contact in Signal

If the other person has Signal, you will see a lock icon next to the handset icon.

Figure 3. The lock icon confirms that Signal protection is enabled for this contact

Step 3. Signal starts dialing.

Figure 4. Calling with Signal

Step 4. As soon as your conversation partner answers the call, Signal will display two words in the center of the screen. You and the person you are talking to should make sure you see the same words. Then you can say that there is no intrusion into your conversation. We advise you to say one word, and let your interlocutor pronounce the second.

Figure 5. Confirmation of contact

4.2. Answering an encrypted voice call

Answering calls on Signal is about the same as on a regular phone.

Step 1. When a call comes to Signal, an image with the words appears in the middle of the screen CALL VIA SIGNAL.

Picture 1. Incoming call Signal

Step 2. Swipe the picture to the rightto answer the call, or to the leftto hang up.

Step 3. When you answer the call, Signal will show two words in the middle of the screen. You and the person you are talking to should make sure you see the same words. Then you can say that there is no intrusion into your conversation. We advise you to say one word, and let your interlocutor pronounce the second.

Figure 2. Receiving an encrypted call to Signal

Step 4. (Additionally) If you call a Signal user from your regular phone dialer, you will be asked if you want to make a secure call. You can choose between an encrypted call or a regular one.