I have been diving into an apk's source code, doing both static analysis with Jadx (same as dex2jar) and dynamic analysis with Frida.
I am trying to replicate the method that signs HTTP requests "signRequest". The thing is that it is only declared in an interface and nowhere in the code is there an actual implementation of that method. When I use Frida to get the instance that uses this method, I can run the method and make it work. The instance in question is like this: com.xxx.yyy.zzz@24d6bf8 but the thing is that the class com.xxx.yyy.zzz, and even the module com.xxx.yyy, do not exist in the source code.
Do you have any idea how this might happen?
EDIT: I've had a hunch and thought that maybe, since I had encountered "antidex2jar" classes in the source code, maybe there were protections against dex2jar making it throw errors, therefore preventing it from decompiling the classes, as I had read somewhere. However, even the smali code on Android-Studio doesn't contain the class.