Cracking

Hello. Sorry for my stupid English.

I verified logic for userinput and binary checksum(1, 2, 3).

and I find password which satisfy binary checksum 1,2,3.

but program caused segmentation fault error.

(I don’t use code and register value tampering).

Please give me a hint.

Attachement is problem picture.

hi woonge. I just solved this.

There are multiple keys that can pass the 3 checksums. Among them, one can lead to a successful execution rather than segment fault (as in your case) or other errors. This key is the flag.

This hint should already allow you to figure it out. If not yet, free feel to let me know and I can provide more hints.

Hello, xusheng

Sorry ’cause this is not really related to the topic, but I’m kinda stuck on the challenge.
I know how the checksum calculation is performed, but I can’t figure out the length of the key and how to calculate it without using bruteforce method.

I wonder if you could give me some hint on this. Thanks in advance