Silent Circle’s Silent Text app offers secure, encrypted texting and file transfer. To start using it, open the Silent Text app by tapping on its icon.
By tapping on the overflow icon on the right at the top of the app, you can open the settings page. Here you will see your account information and settings specific to Silent Text. Under the “Encryption” entry, you will see an option labeled “Encrypt Silent Text.” This creates a passphrase you must enter every time you use Silent Text for additional security, similar to a phone’s lock screen. (Note that all messages sent through Silent Text are encrypted in transit by default. This setting relates to encrypting messages stored on your device.)
To send a message through Silent Text, tap the “+” button at the bottom of the main screen. Select a previous recipient or type a Silent Text username to send a message to a new recipient, then type a message like you would in a typical text application. For any Silent Text you send, you can also tap the Settings icon on the top right to select options for that specific text: whether or not you share location; whether the messages expire after a time period you select (under the “Burn Notice” feature); and other options.
When sending a Silent Text, you can also attach a file up to 100MB in size by tapping the paperclip icon and selecting the file you want to send.