Use APKPure App
Get Hidden Message Free old version APK for Android
Encrypt your text using Cryptography Algorithm.
You can hide your text using this apps and then send to your buddies. While your buddies decrypt message, you can play the game inside this apps. Earn the coins and get the Cryptographer or Cryptoanalyst badge. This apps will help you when you want to talk about your "secret" things. Enjoy :)