> For the complete documentation index, see [llms.txt](https://alham-rizvi.gitbook.io/alhamrizvi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://alham-rizvi.gitbook.io/alhamrizvi/picoctf-writeups/picoctf/forensics/whitepages.md).

# How I Found the Flag

**1. Noticed hidden characters.** The file looked blank, but running `cat -A` on it revealed it was full of non-printable Unicode characters — not actually empty.

**2. Identified the two characters.** Using Python to count unique characters, the file contained only two: a regular space (`U+0020`) and an **em space** (`U+2003`). Two distinct characters = binary encoding.

**3. Decoded the binary.** Mapped em space → `0` and regular space → `1` (tried both ways), then grouped every 8 bits into a byte and converted to ASCII.

**4. Got the flag:**

```
picoCTF{not_all_spaces_are_created_equal_f5d46aff52c6e17f9fd6317b33d2d783}
```

The trick: the file uses **Unicode steganography** — hiding data in visually identical-looking whitespace characters. To the naked eye (and most text editors), the file looks completely blank. But two *different* space characters were used to encode binary data, which decoded straight to the flag.

python script:

with open('whitepages.txt', 'rb') as f: text = f.read().decode('utf-8')

## Map: regular space = 1, em space (U+2003) = 0

bits = '' for c in text: if c == ' ': # U+0020 regular space = 1 bits += '1' elif c == '\u2003': # U+2003 em space = 0 bits += '0'

## Convert every 8 bits to a character

result = '' for i in range(0, len(bits) - 7, 8): byte = bits\[i:i+8] val = int(byte, 2) if 32 <= val <= 126 or val == 10: # printable ASCII or newline result += chr(val)

print(result)


---

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