How to disassemble ipa into parts and find out how it works?

Question

iOS

How to disassemble ipa into parts and find out how it works?
There are two applications that make calls through some kind of tricky protocol.
You need to use them inside a certain office, but you need to find out if the encryption scheme is acceptable (point-to-point) or not (the data goes through a third-party server).
How to do it?

Answer 1

Connect to Wi-Fi and intercept traffic.
And already study it.