Hamming 7,4 codes and I was too lazy to study it :) What about a brute force? The code is 7 bits and the response 4 bits:
```from pwn import *
tab = {}attempts = {}
br = ['0000', '0001', '0010', '0011', '0100', '0101', '0110', '0111', '1000', '1001', '1010', '1011', '1100', '1101', '1110', '1111']
while True:    try:        r = remote('104.154.106.182', 6969)         for i in range(100):            msg = r.recvuntil('DATA:')            print msg             if 'CODE VALIDATED' in msg and code not in tab:                tab[code] = br[attempts[code]]             code = msg.split('CODE: ')[1][:7]            if code in tab:                r.sendline(tab[code])            else:                if not code in attempts:                    attempts[code] = 0                else:                    attempts[code] += 1                r.sendline(br[attempts[code]])         r.interactive()    except:        continue```
It can take a couple of minutes, you can do other challs :)