1018 B
Difficulty
easy - 200/500 punten (met een tool als ghidra is dit echt geen werk)
How To Solve
When you decompile the file with something like ghidra (or gdb if you are feeling naughty), you can see that the main function passes another function called app_start to some GTK functions.
On closer inspection of this app_start function you can see it first checks to see if a keystore file is found and if it is it loads that file and tries to check and see if the loaded key is valid with check_is_key_valid. If no file was found it shows the popup via build_license_key_popup, in which it again uses the check_is_key_valid function.
When looking at check_is_key_valid you can clearly see the format of the key has to be SHTP-AAAA-BBBB-CCCC. Where AAAA and BBBB are hex numbers that have to be larger than 256. On top of that AAAA ^ BBBB has to equal CCCC.
Now you have enough information to generate your own keys. For example: "SHTP-0500-0500-0000"
Flag
IGCTF{Wh0_n33d5_RSA_wh3N_W3_h4v3_XOR}