Stego 15

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This mission has some 24 odd pixels at:

98,0 106,0 69,1 121,1 98,2 109,2 70,3 105,3 73,4 87,4 57,5 115,5 101,6 109,6 112,6 114,6 75,7 67,8 111,8 118,8 78,9 71,10 70,11 122,11 

Assuming starting from in the upper left hand corner. What mysteries to these numbers hold? The ascii values of the x components of each is: </pre> You must cat out the last two chars. The solution is: easy findable with the codes listed down Stego15c.jpg


Some decoding Code:

<?
require_once("imagefrombmp.php");
$im = ImageCreateFromjpeg("stego15b.jpg");
$x= imagesx($im);
$y= imagesy($im);
$hely=-1;
$elozo=0;
$s=$s2="";
$bv=$bv2="";
$db=0;
for($i=0; $i<=$y-1; ++$i){
  for($j=0; $j<=$x-1; ++$j){
    ++$hely;
    $rgb = imagecolorat($im, $j, $i);
	$rgb=imagecolorsforindex($im,$rgb);
	if(!($rgb["red"]>=240 || $rgb["green"]>=240 || $rgb["blue"]>=240)){
	 $s.="$j,$i ";
	 $s2.=$j%6;
	 $s2.=",";
	 $s2.=$i%6;
	 $s2.=" ";
	 $bv.=chr($j);
	 $bv2.=chr($j+$i);
	 $db++;
	};
  };
};

echo "$s<br>$s2<br>$bv<br>$bv2<br>".base64_decode($bv)."<br>$db";
?>


Imagecreate from BMP

<?php
/*********************************************/
/* Fonction: ImageCreateFromBMP              */
/* Author:   DHKold                          */
/* Contact:  [email protected]                */
/* Date:     The 15th of June 2005           */
/* Version:  2.0B                            */
/*********************************************/

function ImageCreateFromBMP($filename)
{
 //Ouverture du fichier en mode binaire
   if (! $f1 = fopen($filename,"rb")) return FALSE;

 //1 : Chargement des ent?tes FICHIER
   $FILE = unpack("vfile_type/Vfile_size/Vreserved/Vbitmap_offset", fread($f1,14));
   if ($FILE['file_type'] != 19778) return FALSE;

 //2 : Chargement des ent?tes BMP
   $BMP = unpack('Vheader_size/Vwidth/Vheight/vplanes/vbits_per_pixel'.
                 '/Vcompression/Vsize_bitmap/Vhoriz_resolution'.
                 '/Vvert_resolution/Vcolors_used/Vcolors_important', fread($f1,40));
   $BMP['colors'] = pow(2,$BMP['bits_per_pixel']);
   if ($BMP['size_bitmap'] == 0) $BMP['size_bitmap'] = $FILE['file_size'] - $FILE['bitmap_offset'];
   $BMP['bytes_per_pixel'] = $BMP['bits_per_pixel']/8;
   $BMP['bytes_per_pixel2'] = ceil($BMP['bytes_per_pixel']);
   $BMP['decal'] = ($BMP['width']*$BMP['bytes_per_pixel']/4);
   $BMP['decal'] -= floor($BMP['width']*$BMP['bytes_per_pixel']/4);
   $BMP['decal'] = 4-(4*$BMP['decal']);
   if ($BMP['decal'] == 4) $BMP['decal'] = 0;

 //3 : Chargement des couleurs de la palette
   $PALETTE = array();
   if ($BMP['colors'] < 16777216)
   {
    $PALETTE = unpack('V'.$BMP['colors'], fread($f1,$BMP['colors']*4));
   }

 //4 : Cr?ation de l'image
   $IMG = fread($f1,$BMP['size_bitmap']);
   $VIDE = chr(0);

   $res = imagecreatetruecolor($BMP['width'],$BMP['height']);
   $P = 0;
   $Y = $BMP['height']-1;
   while ($Y >= 0)
   {
    $X=0;
    while ($X < $BMP['width'])
    {
     if ($BMP['bits_per_pixel'] == 24)
        $COLOR = unpack("V",substr($IMG,$P,3).$VIDE);
     elseif ($BMP['bits_per_pixel'] == 16)
     { 
        $COLOR = unpack("n",substr($IMG,$P,2));
        $COLOR[1] = $PALETTE[$COLOR[1]+1];
     }
     elseif ($BMP['bits_per_pixel'] == 8)
     { 
        $COLOR = unpack("n",$VIDE.substr($IMG,$P,1));
        $COLOR[1] = $PALETTE[$COLOR[1]+1];
     }
     elseif ($BMP['bits_per_pixel'] == 4)
     {
        $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));
        if (($P*2)%2 == 0) $COLOR[1] = ($COLOR[1] >> 4) ; else $COLOR[1] = ($COLOR[1] & 0x0F);
        $COLOR[1] = $PALETTE[$COLOR[1]+1];
     }
     elseif ($BMP['bits_per_pixel'] == 1)
     {
        $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));
        if     (($P*8)%8 == 0) $COLOR[1] =  $COLOR[1]        >>7;
        elseif (($P*8)%8 == 1) $COLOR[1] = ($COLOR[1] & 0x40)>>6;
        elseif (($P*8)%8 == 2) $COLOR[1] = ($COLOR[1] & 0x20)>>5;
        elseif (($P*8)%8 == 3) $COLOR[1] = ($COLOR[1] & 0x10)>>4;
        elseif (($P*8)%8 == 4) $COLOR[1] = ($COLOR[1] & 0x8)>>3;
        elseif (($P*8)%8 == 5) $COLOR[1] = ($COLOR[1] & 0x4)>>2;
        elseif (($P*8)%8 == 6) $COLOR[1] = ($COLOR[1] & 0x2)>>1;
        elseif (($P*8)%8 == 7) $COLOR[1] = ($COLOR[1] & 0x1);
        $COLOR[1] = $PALETTE[$COLOR[1]+1];
     }
     else
        return FALSE;
     imagesetpixel($res,$X,$Y,$COLOR[1]);
     $X++;
     $P += $BMP['bytes_per_pixel'];
    }
    $Y--;
    $P+=$BMP['decal'];
   }

 //Fermeture du fichier
   fclose($f1);

 return $res;
}
?>
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