upload_file2.php

<?php
$key = 'the quick brown fox jumps over the lazy '; //PRIVATE KEY TO ENCRYPT THE MESSAGE(WHICH IS NOTHING BUT OUR KEY)


//FUNCTION TO ENCRYPT THE KEY USING BASE64_ENCODE METHOD


function enc_encrypt($string, $key) {
    $result = '';
    for($i = 0; $i < strlen($string); $i++) {
    	$char = substr($string, $i, 1);
    	$keychar = substr($key, ($i % strlen($key))-1, 1);
    	$char = chr(ord($char) + ord($keychar));
    	$result .= $char;
    }

    return base64_encode($result);
	
}

//FUNCTION TO DECRYPT THE KEY USING BASE64_DECODE METHOD



function enc_decrypt($string, $key) {
    $result = '';
    $string = base64_decode($string);

    for($i = 0; $i < strlen($string); $i++) {
    	$char = substr($string, $i, 1);
    	$keychar = substr($key, ($i % strlen($key))-1, 1);
    	$char = chr(ord($char) - ord($keychar));
    	$result .= $char;
    }

    return $result;
}


$t=array();
	include 'pdf2text.php';		//FILE USED TO EXTRACT TEXT FROM A PDF FILE
	include 'createPDF.php';	//FILE USED TO CREATE A NEW PDF FILE THROUGH PHP
	if (!isset($_SESSION)) session_start();	
	$n=$_POST["name"];			//RECEIVER'S NAME
	$n2=md5($n);					//ENCRYPTED NAME
	$uname=$_SESSION["username"];	//SENDER'S NAME
	$uname=md5($uname);				//ENCRYPTED NAME
	
	
	$con=mysqli_connect("localhost", "root", "","sft");		//CONNECTING TO DATABASE
	
$q="select * from users_entity where Username='$uname'";	//QUERY TO GET ALL FIELDS OF THE PARTICULAR USERNAME(SENDER)
$q2="select * from users_entity where Username='$n2'";		//QUERY TO GET ALL FIELDS OF THE PARTICULAR USERNAME(RECEIVER)


$result=mysqli_query($con,$q);							//RETRIEVING IMAGE NAME OF SENDER
while($row = mysqli_fetch_array($result)) {
  $avatar_name=$row["AvatarName"];
  }
  
  
  	$result2=mysqli_query($con,$q2);					//RETRIEVING IMAGE NAME OF RECEIVER
while($row2 = mysqli_fetch_array($result2)) {
  $avatar_name_2=$row2["AvatarName"];
  }	
  
  
  $pathAndName="./avatars/".$avatar_name;				//PATH OF THE SENDER'S IMAGE
  $pathAndName2="./avatars/".$avatar_name_2;			//PATH OF THE RECEIVER'S IMAGE
  //echo $avatar_name;
  //echo "<br>";
  //echo $pathAndName;
  //echo $pathAndName2;
  $im = imagecreatefrompng($pathAndName);				//LOADING THE SENDER'S IMAGE INTO PHP VARIABLE
  $im3 = imagecreatefrompng($pathAndName2);				//LOADING THE RECEIVER'S IMAGE INTO PHP VARIABLE
 
  $file = $im;
	$width = imagesx($file);
	$height = imagesy($file);		
for($x = 9; $x < 10; $x++) 
	{
		for($y = 0; $y < 72; $y++) 
		{
		$rgb = imagecolorat($file, $x, $y);
			
			$new_g = ($rgb >> 8) & 0xFF;
			$new_b = $rgb & 0xFF;
			$new_r = ($rgb >> 16) & 0xFF;
			$r_bin=decbin($new_r);
			$r_bin = substr("00000000",0,8 - strlen($r_bin)) . $r_bin;
			//echo "<br>before changing ".$r_bin;
			//echo "<br>";
			$t[$y]=$r_bin[7];
			//echo "    after changing ",$r_bin."<br>";
			//echo $new_r." + ".$t." = ".($new_r+$t);
			//echo "<br>";
			//echo $new_r."<br>";
			}
	}
//var_dump($t);
$t3=$t;
$str_data=NULL;
for($i=0;$i<count($t);$i++)
{
	$str_data.=$t[$i];
}
  //$ch=chunk_split($str_data,8," ");
  $ch=$str_data;
  $data_arr=array(); 
  $data_arr=str_split($ch,8);
  //var_dump($data_arr);
  $data_ascii=array();
  for($i=0;$i<9;$i++)
  {
  	$data_ascii[$i]=bindec($data_arr[$i]);
  	$data_org[$i]=chr($data_ascii[$i]);
  }
  
  //var_dump($data_ascii);
  var_dump($data_org);
  $data_org1="";
  $data_org1=implode("",$data_org);
  $data_org1= enc_decrypt($data_org1,$key); //////KEY KEY KEY
  echo $data_org1;
  
  //trying to embed the obtained key into receiver's image
  $file2 = $im3;
	$width2 = imagesx($file);
	$height2 = imagesy($file);		
for($x = 9; $x < 10; $x++) //SELECTING 9TH ROW
	{
		for($y = 0; $y < 72; $y++) //USING PIXELS IN 9TH ROW PIXEL ZERO TO PIXEL SEVENTY ONE TO STORE BINARY VALUES
		{
		$rgb2 = imagecolorat($file2, $x, $y);
			
			$new_g2 = ($rgb2 >> 8) & 0xFF;
			$new_b2 = $rgb2 & 0xFF;
			
			//$new_r+=ord($arr_msg[$i]);
			//$new_r+=100;
			//$new_r-=100;
			$t2=$t3[$y];
			$new_r2 = ($rgb2 >> 16) & 0xFF;
			$r_bin2=decbin($new_r2);
			$r_bin2 = substr("00000000",0,8 - strlen($r_bin2)) . $r_bin2;
			//echo "<br>before changing ".$r_bin;
			//echo "<br>";
				$r_bin2[7]=$t2;
			$r2=bindec($r_bin2);
			//echo "    after changing ",$r_bin."<br>";
			//echo $new_r." + ".$t." = ".($new_r+$t);
			//echo "<br>";
			$new_r2=$r2;//							THE RED VALUE IS ALTERED WITH BINARY DATA AND STORED
			//echo $new_r."<br>";
			$new_color2 = imagecolorallocate ( $file2 , $new_r2 , $new_g2 , $new_b2 );
			imagesetpixel($file2,$x,$y,$new_color2);
		}
	}
$boo2=imagepng($file2,$pathAndName2);
  //Encrypting file using the key decoded from sender's image
  
  
	$username=$_SESSION["username"];
	//$_SESSION['sname']= "File1";
	$name= $_FILES['file']['name'];
	$fileName = substr_replace($name, '_'.$n, -4, 0);
	$_SESSION["filename"]=$fileName;
		$extension = strtolower(substr($name, strpos($name, '.')+1));
		$max_size = 2097152;
		$size = $_FILES['file']['size'];
		$finalname= $name;
		$temp_name = $_FILES['file']['tmp_name'];
		
				if(($extension=='pdf' || $extension == 'doc' || $extension == 'docx') && $size<=$max_size){
					$location ='./File_uploads/';
					//echo 'uploading';
										if(move_uploaded_file($temp_name, $location.$fileName))
					{

						//echo 'uploaded';
						//header("Location: ./readEncrypt.php?msg=1");
						//*********Encrypting file*************
					
						$filename= $location.$fileName;
						$str  = pdf2text($filename);
						$content = $str;
						echo $content;
						
						
						
						$plain_txt = $content;
						function encrypt_decrypt($action, $string) {
							$output = false;
							$encrypt_method = "AES-256-CBC";
							$secret_key=$data_org1;
							$secret_iv = '1111';
							// hash
							$key = hash('sha256', $secret_key);
							// iv - encrypt method AES-256-CBC expects 16 bytes - else you will get a warning
							$iv = substr(hash('sha256', $secret_iv), 0, 16);
							if( $action == 'encrypt' )
							{
								$output = openssl_encrypt($string, $encrypt_method, $key, 0, $iv);
								$output = base64_encode($output);
							}
							else if( $action == 'decrypt' ){
								$output = openssl_decrypt(base64_decode($string), $encrypt_method, $key, 0, $iv);
							}

							return $output;
						}
						
						$encrypted_txt = encrypt_decrypt('encrypt', $plain_txt);
						
						createPDF($encrypted_txt);
						header("Location: ./PROFILE/student_profile.php");
					
					}
					else{
						echo $location.$fileNam."hello";
						//header("Location: ./index.php?msg=1");
					}
				}
				else{
					header("Location: ./index.php?msg=2");
					//echo 'file must be less than 2 mb and should be pdf doc docx';

				}
  
  
  
?>