title: How to make a bluetooth connection secure?
body: <p>I have kind of confusion about BLE secure connection. </p>
  
  <p>I am working on an IoT project. I am using ESP32 development board. At one point of my project I have to send some data like Email and Password from android phone to ESP32 connected over BLE. </p>
  
  <p>My question is it how to make it most secure? since i have to transfer user password over it. 
  Is there any difference between paired connection vs unpaired connection?
  which encryption method I should use? </p>