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There is a secret word associated with this image that will be clear if it is decrypted properly. What is that word?

Full size image: http://i.imgur.com/XMdDfAM.jpg enter image description here

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  • $\begingroup$ There seem to be some heavy JPEG artifacts in the image. Can you confirm that these are irrelevant when trying to decode the message? $\endgroup$ – jarnbjo May 18 '15 at 1:57
  • $\begingroup$ @jarnbjo those artifacts are irrelevant. $\endgroup$ – Quark May 18 '15 at 2:04
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I hesitate to say

STAR

since

a mere width/height adjustment seems a bit easy.

Method:

It's visually recognizable as an image that has been skewed in width. I converted it to a BMP, opened it with a hex editor, and started guessing at some values to adjust the width field. After 3 or 4 attempts, I stumbled upon one which made it readable enough to obtain the above, and did not attempt to further refine the value.


Edit by Author:

The "ideal" dimensions alluded to in the above method is when the dimensions are square. Multiplying the image dimensions together, you get $1337 * 1914 = 2559018$.
The square root of this is 1599.7, so make the image dimensions 1600 X 1600 and you get the below image:
enter image description here

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    $\begingroup$ can you explain your answer (such as how you figured it out and perhaps the decrypted image)? Yes it is pretty simple for someone in this field of study since it's a common phenomenon encountered when debugging. $\endgroup$ – Quark May 18 '15 at 2:06
  • $\begingroup$ @Quark Method added. $\endgroup$ – Ayefork May 18 '15 at 2:16
  • $\begingroup$ Could you add an image of what you got? I ended up with something that looks similar to a star, but I'm not sure if that's just a coincidence. $\endgroup$ – MisterEman22 May 18 '15 at 2:32
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    $\begingroup$ Sorry, but I still don't really understand exactly how to do it. If you could link what type of software would be used, or something that explains it in a step by step fashion I'd appreciate it. The way I'm reading it right now is resize the picture to 1600x1600, and clearly there's more to it than that. $\endgroup$ – MisterEman22 May 18 '15 at 3:53
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    $\begingroup$ @MisterEman22 Basically the width and height information of the image was changed, so all the pixel information (RGB) is there but the picture goes to the next row before it should. There are many ways to fix this, one is to edit the image width and height values in the image header. Certain file types (such as BMP used by Ayefork) have values that can easily be edited. Personally I used GIMP to convert the image to a .PPM and then edited the 4th line in the header (opening the image with notepad++) which corresponds to width/height. $\endgroup$ – Quark May 18 '15 at 7:13
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The image contains a little bit more than in Ayefork's answer.

The text actually reads:

The secret message is: STAR

You can find a decoded version of the image here and Java source code for decoding the image here.

Description:

The original image has been split into 6 vertical slices, each 263 pixel wide and using some strange interleaving pattern, been skewed into the 1337 pixel wide encoded image.

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  • $\begingroup$ The Java source code is a nice addition. Although overkill for this case, this type of method can be modified for situations when the encryption isn't just a simple skew. I may make a puzzle in the future that needs something similar to solve it. $\endgroup$ – Quark May 18 '15 at 2:54

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