# Find the secret phrase in this encrypted image (part 3)

Welcome to part 3 of Quark's quest to make an image puzzle that isn't solved in under an hour. Like the last one, this will be much more difficult than the last.

In the below encrypted message, there are stages that lead from one to the next. There are two main words to discover, one at the ~75% completion mark, and one at the finish line. Put them together and you'll have a phrase related to computing.

What is that phrase?

Hints definitely aren't needed to solve this but if it goes past a day or two I'll start giving hints. However, if this is solved under two hours then I'll admit that I underestimate this puzzling community and I'll be forced use drastic measures for part 4.

Note: The "ovals" in the picture are different sizes, ignore this because I made this sloppily in Paint. This was originally supposed to make smart puzzlers go "well he probably doesn't want us measuring their radii/center position so I'll ignore it" but I realize it's better to explicitly state it.

Note 2: There is no extra information in this puzzle other than the size thing mentioned above. I realized there is a phrase related to computing that is discovered around the 40% completion mark but this is not related to the answer and is just a hint on how to progress further.

• The "circles" have different sizes. Is this intentional? – leoll2 May 19 '15 at 18:28
• @leoll2 I literally edited the post to include this note the same second you posted that comment lol. – Quark May 19 '15 at 18:29
• Just saw this... I guess I have ten minutes to beat you to an hour =P – 2012rcampion May 19 '15 at 19:02
• @2012rcampion I made this one a lot tougher than the last one, good luck solving it in 10 minutes xD – Quark May 19 '15 at 19:09
• Just noticed the trick... you're lucky I didn't immediately reach for Histogram this time! – 2012rcampion May 19 '15 at 19:20

(No spoiler tags because they're messing with the line breaks...)

First we do a trivial reshaping of the image to un-distort it:

img = Import["http://i.stack.imgur.com/fIAv4.png"]
rectified = Image[ArrayReshape[ImageData[img, Automatic], {400, 399, 3}], "Byte"]


After noticing that the black pixels are not all exactly black, I extracted the lowest bit from each pixel:

bitImg = Image[Mod[ImageData[rectified, Automatic], 2], "Bit"]


ZBEFR PBQR is MORSE CODE rot13'd. This suggests that part of the puzzle will be decoded using Morse code. After extensive randomness testing on the data burst at the top of the image, I switched to analyzing the dots.

First I played around with separating the color channels, since the pure/saturated primary colors suggested per-channel binary data. This lead nowhere.

Finally I pulled up the Morse code Wikipedia page, and immediately noticed that H is encoded as four dots. Where had I seen those before? The red dots at the top of the image. The two letters I know, T (-) and E (.) are both single dots: corresponding to the dots on either side of the four red ones. Put it all together and you get THE! I realized that the colors were a Morse code substitution cipher with the following mapping:

RED   => DOT (·)
BLUE  => DASH (-)
BLACK => LETTER SPACE (/)
GREEN => WORD SPACE ( )


This allows us to decode the dots as:

 bkrrrrkrgrbbrkrbkrrrkrrrgrrkrrrgrkbbkbrrrkrkbrrkbrrkrkbrr
-/..../. .--./.-/.../... ../... ./--/-..././-../-.././-..
T  H  E    P  A  S  S    I  S   E  M  B  E  D  D  E  D


Entering embedded as the password into a suitable online decrypter, we obtain the following image file (chip.png):

Therefore the answer is EMBEDDED CHIPS.

• Nice progress so far, you probably don't need me to say it but you're definitely on the right track. – Quark May 19 '15 at 19:46
• Good job you got the whole thing, I think you can safely say you're a puzzles guy =) – Quark May 19 '15 at 23:20
• I kind of expected the data burst at the top of the bit-slice image to be raw bytes (I've done that before to embed Mathematica code into an image), so I spent way too long trying to figure out what encoding you were using... It took me an hour to realize that you probably just used an online encrypter like a normal person =) – 2012rcampion May 19 '15 at 23:21
• Wow! Super-complex puzzle, @Quark - so great work 2012rcampion for unravelling all the layers! – Rand al'Thor May 19 '15 at 23:21
• Which picture did you decrypt with the password 'embedded' to get the final answer? – Bailey M May 20 '15 at 13:03

From 2012rcampion's answer, we get "morse code".
From this, we can think there's a message in morse hidden in the image;
Morse code needs four symbols: (-), (.), ( ), (/)
In the picture, the ovals come in four colors, so maybe each color stands for one symbol.
Green is the least frequent so it's the word separator, /;
the letter separator can only be black, since red and blue can come in pairs;
red has to be the dot, since the second letter, rrrr, doesn't make sense as dashes (while as dots, it's "h").

recap:
(-) blue
(.) red
( ) black
(/) green

Substituting, we obtain
- .... . / .--. .- ... ... / .. ... / . -- -... . -.. -.. . -..
In morse, it gives:
THE PASS IS EMBEDDED

• 75% finished, now for the final stretch. This last part may require research on the topic of one of the tags. – Quark May 19 '15 at 21:18
• Wow, I wish I had scrolled down before trying to work that out myself... I'm a software guy, not a puzzles guy =) – 2012rcampion May 19 '15 at 22:59
• Conversely, I'm a puzzles guy and not a software guy. I wouldn't have been able to do anything without your answer, nor I have any idea on how to proceed from this point. Hope you can deal the final blow! – byserpas May 19 '15 at 23:15
• oh wait you did, never mind. congrats! – byserpas May 19 '15 at 23:20