That image was released on onion 3 server-status page. In map 2014, page4.jpg is image with magic square. This can be fair to then say they do not contain any valid, encrypted or not, Outguess data in them.Īs a bonus, it has to be noted that the 400x400 dpi we have for the other images is the default for GIMP.Īll cicada image files, jpgs and pngs from 2012, 20įiles are supposed to be originals, but i havent double chack every single one. From the previous paragraph we now that the images with these fields set to any other value cannot have been output from a vanilla version of Outguess. Last runes p4: ff e0 00 10 4a 46 49 46 00 01 01 00 00 01 00 01 00 00 YESĪs can be seen, images with a density unit set to unknown and X Y densities set to 1x1 correspond to images with readable outguess data in them. Now lets look at the APP0 marker for images given to 2014 (the exercise for earlier images is left to the reader):Ĭover: ff e0 00 10 4a 46 49 46 00 01 01 00 00 01 00 01 00 00 YES This is interesting to notice since image processors in general tend to give useful values for these fields as they will be used for printing and later editing. It has to be noticed that the APP0 marker will appear as JFIF 1.1 with a void density unit and X Y densities set to 1x1. Write_JPEG_file (FILE *outfile, image *image)Ĭinfo->JFIF_major_version = 1 /* Default JFIF version = 1.01 */Ĭinfo->density_unit = 0 /* Pixel size is unknown by default */Ĭinfo->X_density = 1 /* Pixel aspect ratio is square by default */ When looking at the outguess JPEG wrapper code for the writing of the output, this looks like that: When looking for clues about which program was used to generate a given output, one has to look at the header construction. Outguess uses its own JPEG wrapper code around libjpeg. The latter question is much more easier to answer and provides a clear answer about the possibility of valid Outguess data in a picture. Let's rephrase the original question from "Is there valid outguess data in this image ?" to "Can this image be an output of the Outguess program ?". Consequently, the compression level of an image may give a clue about the presence of outguess, but this is not enough to draw any conclusion yet. When creating the new JPEG, the default compression is 75, and can be set using -p to a value between 75 and 100. Before embedding data into an image, OutGuess can determine the maximum message size that can be hidden while still being able to maintain statistics based on frequency counts."Īs can be noticed, Outguess creates a new JPEG statistcally equivalent to the one given as an input. As a result, statistical tests based on frequency counts are unable to detect the presence of steganographic content. "For JPEG images, OutGuess preserves statistics based on frequency counts. : i havent even open it in PS, no time atm : probaly no outgues, i am pretty sure the re isn none, but further tests needed 14 ALL SORTS OF UNRELTATED STUFF AND MASSOS POSTS IN BETWEENĪnd my anylsis needs a lot more testing to be sure, if there are no squares on uniform background it does not necessarily mean that there is no outguess, it appears that if jpg is big enough and message hidden with outgues is short, background is not touched by outguess, as you can see on first jpg of 2014, outguess is in and background is fully uniform black.9 Testing outguess by putting mesage in sample picture.3 All cicada image files, jpgs and pngs from 2012, 20.
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