How to protect app IPA from hacks if reverse engineering is possible

Question

Recently we developed and published a mobile banking app on the app store, for a big banking organization. The bank hired a security firm to perform ethical hacking over the

Answer 1

I was recently researching over this and I found this article helpful, especially the part quoted:

The code for a native app is stored in the form of a binary executable file, which is further encrypted; its decryption is performed only when the executable file is loaded by the processor into the random access memory and the whole decryption process happens at the hardware level. That is why it is very hard to create offline decryption tools. The only way to decrypt encrypted binary data is on a jailbroken device with a few special tools installed.

Security in iOS: Protecting .ipa File Content by Stoyan Stoyanov