Facebook introduced a new version of the Messenger for Android that has one-one encrypted messaging feature know as Secret Conversations. This feature is only available to a limited number of the Facebook messenger’s first, and will be implemented to others for later this summer.
You also have to explicitly start a Secret Conversation in Messenger. Encryption isn’t the default mode, and encrypted messages are not integrated into the primary thread of your conversations with a given contact.
How to use Secret Conversations:
Step 1: Click on the profile section, which is the person icon on the upper right of the screen. Make sure the Secret Conversations slider is activated.
Step 2: Choose the contact you want to start an encrypted conversation with in messenger. Now click Secret conversation which will bring you to new tab.
Step 3: Now your screen will turn to black theme, and you’re ready to go.
Note: To view an open secret conversation thread just choose it from the list of open message threads on the main screen of the app.
Secret Conversations work almost like regular Facebook messages but not quite. You can send text, emoji, stickers, and pictures; however, gifs, videos, voice calling, and payments are not supported.