Reverse Engineering Android Apps
Reverse engineering in general is a tricky business and sometimes not very orthodox. So, why bother to write this article?
Well, sometimes reverse engineering is also for something good. It started when my wife dusted off her watch. We had a huge unpleasant surprise when we found that the companion app is not available anymore on Google Play! The watch is completely useless without the companion app, as you can’t even set the time on it… Because I hate to throw away a perfectly working watch I decided to create an app for it myself.
My first instinct was to find an older phone with the app still alive and to use a BLE sniffer to reverse engineer the BLE protocol. But I didn’t find the application installed on any old phones. I found the application online but the application cannot be used anymore as it was using some online services which are offline now…
Next obvious step was to decompile the application to get the communication protocol and also the algorithms behind the sleep & activities. This is how our story begins ;-).