In this challenge we get an nro file. It turns out that it's a game of the Switch console. When loading the game in the
yuzu emulator we get the instructions to encrypt the following text:
f42df92b389fffca59598465c7a51d36082ecfea567a900e5eac9e5e9fb1
. Whilst searching through the binary I found the
following string shuffle*whip$crush%squeeze
. Those are names for the basic functions of the Spritz
cipher.
Thw following python program encrypts our text and prints the flag:
from spritz import Spritz
import binascii
spritz = Spritz()
K = bytearray('shuffle*whip$crush%squeeze\0')
M = bytearray.fromhex('f42df92b389fffca59598465c7a51d36082ecfea567a900e5eac9e5e9fb1')
C = spritz.encrypt(K, M)
print C