A reference from "black hat' movie 2015. The hacker cracks Encrypted code. How a malware has Encrypted code ended in ? And how to crack that ?

Any information or tutorial or article would be appreciated. 

I do reverse engineer using IDA pro ( static analysis ). 
 

OT: Was not a great film by the way, they can do it a lot better!

Not only malware but also normal application can contain encrypted code.

How to reverse engineering them? A lot depends on the technique that was used for encryption but as you can think, if the software run then can be reversed.

Usually the decryption routine is inside the code so it can be traced, when you have the key to decrypt the code all become easy.

What are you trying to accomplish?

You can take a look (it is not encryption but the concept is the same) at:

https://tuts4you.com/download.php?view.2989

https://tuts4you.com/download.php?view.3576

crystalboy