> For the complete documentation index, see [llms.txt](https://ctf.zeyu2001.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ctf.zeyu2001.com/2021/bcactf-2.0/more-than-meets-the-eye.md).

# More Than Meets the Eye

## Problem

My friend just sent me this file, but it looks pretty empty. Are you able to see anything?

## Solution

Opening up the file in a hex editor, we can see that the "empty space" is essentially repetitions of either `E280 8BE2 808C` or `E280 8CE2 808C`.

![](/files/-McEaQimkTRDZ_u4_Z38)

We can convert this to binary where `E280 8BE2 808C` -> 0 and `E280 8CE2 808C` -> 1.

```python
from Crypto.Util.number import *

with open('zwsp.txt', 'rb') as f:
    data = f.read()

i = 0
curr = []

bin_string = ''

for char in data:
    if char not in b'Pretty empty over here':
        i += 1
        curr.append(char)
        if i % 3 == 0:
            i = 0
            print(curr)

            if curr[-1] == 139:
                bin_string += '0'
            else:
                bin_string += '1'

            curr = []

print(bin_string)
print(int(bin_string, 2))
print(long_to_bytes(int(bin_string, 2)))
```

![](/files/-McEaWThkFY5_9iZJkvZ)