#!/usr/bin/env python3

def check_key(key):
	if len(key) != 13:
		pass
        #return False

	diff = [83, 0o113, 89]
	expected = b'\x00\x00\x00\x7e\x13\x16\x7f\x1c\x62\x63\x7d\x14\x08'

	for i in range(len(key)):
		print(chr(expected[i] ^ diff[i % len(diff)]))
		if ord(key[i]) ^ diff[i % len(diff)] != expected[i]:
			pass #return False

		diff[i % len(diff)] = ord(key[i])

	return True

def main():
	print("Enter key to decrypt files:")
	key = input("> ")

	if check_key(key):
		print("Valid!")
	else:
		print("Invalid!")

if __name__ == "__main__":
	main()