I am a 3rd year student pursuing an Electronics and Computer science in need for an idea for a major project. I am comfortable working with microcontrollers like Arduino, ESP8266, ESP32 etc.. and understand a fair portion of coding (C,C++,Python).I've made many basic projects like home automation and a smart healthcare but since this is my 'major' project, I hoping to make something different.
Thank you for your time

 

Build two apps for Android (in C++ and/or Java), where 1st Android (which can only run bluetooth) can communicate to another Android phone text app via bluetooth. The 1st Android takes text input, encrypts it (AES256 EC using PSK), and sends that to the text app on 2nd Android. The 2nd Android then sends the message to some other device via cell network. If you wish to get fancy, build in ability to grab a public key for encrypting. In basic terms, air gapped PGP.

Alternatively, build the 1st device/app in Arduino or whatever you like.

This whole thing is in the realm of keeping hackers from collecting private communication from your cell enabled device.