Cracking

Are there any hint for this challenge, i’m working with this for some days :/

Yep.
"checksum is the way" - not so good hint, "xor is the way"  😉

Can someone give me hint about how to determine the password length?

check vigenere cryptography algorythme, now i need help looks like i cant brute force the fifth charactere of the signature stocked inside the damn binary