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stegano 22


henry123456789's Avatar
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0 0

I find stegano 22 the most difficult one compared to the 21 stegano challenges before it . Since there are absolutely no helpful hints concerning stegano 22 in the forum , I begun to read the article as I could not go further and I summed the article like this :

The first marker which is FF is to anounce the beginning of a new marker and the second contains a code that specifies the marker type .

a file must begin with SOI maker and end with EOI marker .

SOI = the start of image FFD8

JFIF marker = file signature (FFE0)

FILE IDENTIFIER = 4A, 46, 49, 46, 00

FF DB = specifies one or more quantization table

FF C0 = Indicates that this is a progressive DCT-based JPEG, and specifies the width, height, number of components, and component subsampling (e.g., 4:2:0).

FF C4 = specifies one or more huffman tables

FF DA = Begins a top-to-bottom scan of the image . This marker specifies which slice of data it will contain, and is immediately followed by entropy-coded data.

THE REST IS FF00 to the end of the document then FFD9 which is the EOI

In addition to that I got some information about the steg22.jpg metadata :

ExifTool Version Number : 10.08 File Name : steg22.jpg Directory : C:/made File Size : 69 kB File Modification Date/Time : 2015:12:25 23:07:40+01:00 File Access Date/Time : 2015:12:25 23:07:40+01:00 File Creation Date/Time : 2015:12:25 23:07:40+01:00 File Permissions : rw-rw-rw- File Type : JPEG File Type Extension : jpg MIME Type : image/jpeg JFIF Version : 1.01 Resolution Unit : inches X Resolution : 96 Y Resolution : 96 Image Width : 799 Image Height : 300 Encoding Process : Baseline DCT, Huffman coding Bits Per Sample : 8 Color Components : 3 Y Cb Cr Sub Sampling : YCbCr4:2:0 (2 2) Image Size : 799x300 Megapixels : 0.240

I am stuck and could not find my way to what should I do as the information above could not help me solve the challenge and I have no clue to what should I do .


rex_mundi's Avatar
☆ Lucifer ☆
15 0

An article on Steg22.

Hello everyone, if you are here that means you are stuck about how to attack this challenge. For this challenge, you will need to read up on JPEG header information and how to convert decimal numbers to hexadecimal numbers. In this article, you will learn a little about JPEG headers and how to look at this challenge Outside the box.

That tells you everything you need to know.

When you've completed this one, you'll understand why 454447415244 who made stego 22 said the above was a massive spoiler.

You don't need to learn anything about jpegs either, just read that quote again and again, and think about what it actually says.


henry123456789's Avatar
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So , Since 18:00 until now 01:52 approximately 8 hours I have been analyzing , rereading , studying and meditating on this : ** "read up on JPEG header information and how to convert decimal numbers to hexadecimal numbers" **

but when I opened the JPEG image in a hex editor , all what I saw are characters and their hexadecimal values . Thus I am wondering where are these decimal numbers that must be converted to hexadecimal ?!!!!! . However if the contrary is meant then I converted all the value of each marker to decimal but I did not get anything special except of numbers that when translated to ASCII give no meaning at all . I even considered some hexadecimal values like decimal numbers and tried to convert them to hexadecimal (which is a madness because these are hexadecimal values ) then I got nothing special except of normal numbers like for example :

A sample :

decimal = 46 49 46 00 01 01 01 00 60 00 60 00 00

hexadecimal = A 2E 31 2E 0 1 1 1 0 3C 0 3C 0 0

decimal = 00 43 00 08 06 06 07 06 05 08 07 07 07 09 09 08 0A 0C 14 0D 0C 0B 0B 0C 19 12 13 0F 14 1D 1A 1F 1E 1D 1A 2C 2C 20 24 2E 27 20 22 2C 23 1C 1C 28 37 29 2C 30 31 34 34 34 1F 27 39 3D 38 32 3C 2E 33 34 32

hexadecimal= 0 2B 0 8 6 6 7 6 5 8 7 7 7 9 9 8 13 C D E 14 18 1B 14 16 17 1C 25 1D 1E 1F 22 22 22 1B 27 26 20 21 22 20........

I am sorry Rex_mundi but I cannot figure out my way through your hint . May be , if you do not mind, some more little tiny clarification can help me :)


rex_mundi's Avatar
☆ Lucifer ☆
15 0

Thus I am wondering where are these decimal numbers that must be converted to hexadecimal ?!!!! It's a 2 dimensional image, think what those 2 dimensions are, then read that quote from the article again.


henry123456789's Avatar
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0 0

I solved it but I never thought it to be solved that way . I must admit it : I am not satisfied with myself this time because if you did not help me rex_mundi I would never ever be able to solve it . I think in 10000 challengers may be one will figure it out by himself .