In this reverse challenge we were given a ELF (look at generic_crackme_redux):
So the first thing to do is to open it in ghidra and understand the business logic:
This is the main function:
![main function](main.png)
We are asked to input a string, then is called a check function on the input, the core of the check is:
![check function](check.png)
So the flag is:```flag{70517}```