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Brief description of php hash operation on files

墨辰丷Original: 2018-06-11 17:00:312238browse

This article mainly introduces the method of hashing files in PHP, involving hashing techniques for files. It is of great practical value. Friends in need can refer to it.

The example of this article tells about the hashing of files by PHP. Method for performing hash operations. The details are as follows:

This code is very useful. If you download a file and the website provides a hash result, you can perform a hash operation on the file you downloaded to verify whether the downloaded file is correct.

<html>
<head>
  <title>Hash (Check) Files</title>
  <style type=&#39;text/css&#39;>
   #ok{color:green;}
   #nono{color:red;}
  </style>
</head>
<body>
 <?php
   if(!empty($_FILES)){
   if ($_FILES["file"]["error"] > 0){
    switch($_FILES["file"]["error"]){
     case 1:
     echo "<b id=&#39;nono&#39;>Error: The uploaded file exceeds the upload_max_filesize directive in php.ini</b><br>";
     break;
     case 2:
     echo "<b id=&#39;nono&#39;>Error: The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.</b><br>";
     break;
     case 3:
     echo "<b id=&#39;nono&#39;>Error: The uploaded file was only partially uploaded.</b><br>";
     break;
     case 4:
     echo "<b id=&#39;nono&#39;>Error: No file was uploaded.</b><br>";
     break;
     case 6:
     echo "<b id=&#39;nono&#39;>Error: Missing a temporary folder.</b><br>";
     break;
     case 7:
     echo "<b id=&#39;nono&#39;>Error: Failed to write file to disk.</b><br>";
     break;
     case 8:
     echo "<b id=&#39;nono&#39;>Error: A PHP extension stopped the file upload.</b><br>";
     break;
     default:
     echo "<b id=&#39;nono&#39;>Unknown error occured.</b><br>";
    }
   } else {
    echo &#39;Upload: &#39; . $_FILES[&#39;file&#39;][&#39;name&#39;] . &#39;<br>&#39;;
    echo &#39;Type: &#39; . $_FILES[&#39;file&#39;][&#39;type&#39;] . &#39;<br>&#39;;
    echo &#39;Size: &#39; . (round($_FILES[&#39;file&#39;][&#39;size&#39;] / 1024, 2)) . &#39; Kb<br><br>&#39;;
    if(array_search($_POST[&#39;algo&#39;], hash_algos())===false){
    echo &#39;Unknown hashing algorithm requested.<br>&#39;;
    } else {
    echo &#39;Hashing Algorithm: &#39;. $_POST[&#39;algo&#39;] . &#39;<br>&#39;;
    $hash = hash_file($_POST[&#39;algo&#39;], $_FILES[&#39;file&#39;][&#39;tmp_name&#39;]);
    echo &#39;Calculated hash: &#39; . $hash . &#39;<br>&#39;;
    if($_POST[&#39;exphash&#39;]!==&#39;none&#39; && !empty($_POST[&#39;exphash&#39;])){
      echo &#39;Expected hash:   &#39; . $_POST[&#39;exphash&#39;] . &#39;<br><br>&#39;;
      echo ($hash==$_POST[&#39;exphash&#39;])? &#39;<b id="ok">Hash matched expected value.</b>&#39; : &#39;<b id="nono">Hash did not match expected value.</b>&#39;;
      echo &#39;<br>&#39;;
    }
    }
   }
   ?>
   <br>
   <button onClick="document.location.reload(true)">Again</button>
    <?php
   } else {
  ?>
  <form action="" method="post" enctype="multipart/form-data">
   <input type="hidden" name="exphash" value="none">
   <label for="file">Filename:</label>
   <input type="file" name="file" id="file">
   <input type="submit" name="submit" value="Submit" /><br>
   <label>Expected hash(optional): <input type="text" name="exphash" size="100"></label>
   <br><br>Choose an algorithm (This is the list of all the available algorithms in your php installation)<br>
   <?php
   foreach(hash_algos() as $algo){
    if($algo==&#39;md5&#39;){
    echo "<label><input type=&#39;radio&#39; name=&#39;algo&#39; value=&#39;$algo&#39; checked=&#39;checked&#39;>$algo</label><br>";
    } else {
    echo "<label><input type=&#39;radio&#39; name=&#39;algo&#39; value=&#39;$algo&#39;>$algo</label><br>";
    }
   }
   ?>
  </form>
 <?php
   }
  ?>
</body>
</html>

##Summary: The above is the entire content of this article, I hope it can be helpful to everyone’s learning help.

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