> For the complete documentation index, see [llms.txt](https://the-winrars.gitbook.io/writeups/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://the-winrars.gitbook.io/writeups/2020-writeups/zh3r0-ctf/crypto/dozen-bases.md).

# Dozen Bases

From listening to the audio, I realised that it was DTMF tones immediately. (The website I usually use: <http://www.dialabc.com/sound/detect/index.html> was broken, so I had to do it another way, using a weird tool or somethin and then manually correct stuff with audacity, but lets pretend it worked to make things simple) Once we decoded the tones, we got a string of characters, which was 'A288439640A3A140997B8A9945987B8844838B85847B419298407B447B978186437B99454192877B5870655AA5' From the title, we can guess that this is base12, and since there was a gap between each 2 tones, I guessed that it was just each 2 tones was the base12 of a character. I wrote a short python script to convert it to the flag.

```python
line = "A288439640A3A140997B8A9945987B8844838B85847B419298407B447B978186437B99454192877B5870655AA5"
print(len(line))
n = 2
x  = [line[i:i+n] for i in range(0, len(line), n)]
o = ""
for i in x:
  o += chr(int(i,12))
  b.append(chr(int(i,12)))
print(o)
```

## Flag: zh3r0{y0u\_ju5t\_h4cked\_1nt0\_4\_saf3\_u51ng\_DTMF}