# unimod
![Screenshot_20220429_103932](https://user-images.githubusercontent.com/75040566/166264683-f29592fa-8967-4650-a15e-c68564d6d874.png)
in this chall he gave me encryption code ```python import random
flag = open('flag.txt', 'r').read()ct = ''k = random.randrange(0,0xFFFD)for c in flag:    ct += chr((ord(c) + k) % 0xFFFD)
open('out', 'w').write(ct)
```he picks a random key between 0 and 65533so key < 10e9 then we can do a bruteforce . 
```python
f = open('out','r').read()print(f)
for i in range(0 , 0xFFFD ):    h = ''    for j in f:        h+= chr(( ord(j) -i )% 0xFFFD)    if 'flag' in h :        print(h)```
flag: flag{4e68d16a61bc2ea72d5f971344e84f11}