This app allows you to protect your conversations.
Officelock by eBuddy is a secure and ecnrypted messanger. The app allows you to send messages, pictures and other files to your co-workers. One of the main features of Officelock is that your messages will be deleted once they are seen - and by the way, because they are encrypted, only you and the sender/receiver can read them.
The app is supported on Android 4.4 or later. There is also a version for iPhone.
You can download and use this app for free.
Image: Google Play