Mind Palace II
[PPC]
Mind Palace II
It's time to strain your brains.
URL: nc 212.47.229.1 33002
Recon
The server sends a message that we have to 'decrypt'. We only have to use a ROT-13 substitution cipher. This can be automated with a script, revealing the flag after about 50 or so messages.
Code
import string
import pwn
def rot13(msg):
a = string.ascii_uppercase
return ''.join([a[(a.index(c) + 13) % len(a)] for c in msg])
conn = pwn.remote('212.47.229.1', 33002)
conn.recvuntil('Mess')
res = True
while res:
res = conn.recv()
if b'{' in res:
print(res.decode().split('\n')[0])
break
msg = res.decode().split('\n')[0].split(' ')[1]
dec = rot13(msg)
print(f'{msg} -> {dec}')
conn.send((dec + '\n').encode())
conn.close()
Flag
FLAG{Y0U_V3RY_F45T3R_CRYPT0GR4PH}