CryptoChatApp Installation: APK: link here or, https://github.com/RandomCodersVision/CrytoChatApp/blob/master/app/build/outputs/apk/debug/app-debug.apk Ciphers used: Feistel Cipher Affine Cipher Shifting cipher Contributor can support with more complex algorithm like RSA DES AES RABIN Implemented Ciphers are found here. Note: Do not forget to replace Firebase service key file with Your service key. Link: SetupLink Setting up firebase: Video how to Setup Woking implementation: Wokring Demo