Tags: crypto

Rating:

**Category:** Crypto

**Points:** 429

**Description:**
> Everyone's favorite guess god Tux just sent me a flag that he somehow
encrypted with a color wheel!
>
> I don't even know where to start, the wheel looks more like a clock than a
cipher... can you help me crack the code?
>
> **Author:** Boolean
>
> **Given:** ciphertext.jpg && color-wheel.jpg

## Writeup
This one took me a while to figure out for some reason (lol). The hint gave me
the idea that the colors in the chart were corresponding to the numbers on the
clock (1-12), but I was just a tiny bit wrong. The color wheel had values
**(0-11)**, but in hex *obviously...* (sarcasm). Here is my edited version:

Now, with this and our ciphertext, we can start plugging and chugging values. Our
result is the following:

86 90 81 87 a3 49 99 43 97 97 41 92 49 7b 41 97 7b 44 92 7b 44 96 98 a5


Translating this from hex to ASCII, doesn't give us anything but gunk...

....¢I.C..A.I{A.{D.{D..¥


After a while of staring at this stupuid color wheel and hex values I derived from
it, I started noticing that  86 90 81 87  represents  flag  and the a3 and
a5 values are two apart (have to be curly braces). It finally hit me that this is
in base12. This changes our ascii representation of these values:

41 -> 1 62 -> J 83 -> c a4 -> |
42 -> 2 63 -> K 84 -> d a5 -> }
43 -> 3 64 -> L 85 -> e
44 -> 4 65 -> M 86 -> f
45 -> 5 66 -> N 87 -> g
46 -> 6 67 -> O 88 -> h
47 -> 7 68 -> P 89 -> i
48 -> 8 69 -> Q 8a -> j
49 -> 9 6a -> R 8b -> k
4a -> : 6b -> S 90 -> l
4b -> ; 70 -> T 91 -> m
50 -> < 71 -> U 92 -> n
51 -> = 72 -> V 93 -> o
52 -> > 73 -> W 94 -> p
53 -> ? 74 -> X 95 -> q
54 -> @ 75 -> Y 96 -> r
55 -> A 76 -> Z 97 -> s
56 -> B 77 -> [ 98 -> t
57 -> C 78 -> \ 99 -> u
58 -> D 79 -> ] 9a -> v
59 -> E 7a -> ^ 9b -> w
5a -> F 7b -> _ a0 -> x
5b -> G 80 -> ' a1 -> y
60 -> H 81 -> a a2 -> z
61 -> I 82 -> b a3 -> {


Now decoding with our base12 ASCII representation gives us the flag.

## Flag
flag{9u3ss1n9_1s_4n_4rt}

## Resources
[ASCII Chart](http://www.asciitable.com/)