title: Aspose.PDF for .NET multiple signatures - all signatures are invalid except the last one
body: <p>I sign a PDF file with multiple signatures using Aspose.PDF for .NET.When I open the file by Adobe Reader, all signatures show: &quot;The Document has been altered or corrupted since the Signature was appiled&quot; except the last one.How can I do?Thanks!
  This is my code base on the official example</p>
  <p><a href="https://docs.aspose.com/pdf/net/improved-and-flexible-pdf-signing-mechanism/" rel="nofollow noreferrer">https://docs.aspose.com/pdf/net/improved-and-flexible-pdf-signing-mechanism/</a></p>
  <pre><code>            string file = &quot;E:\\Temp\\0.pdf&quot;;
              // Create FormEditor object
              FormEditor editor = new FormEditor();
              editor.BindPdf(file);
              // Add signature fields
              editor.AddField(FieldType.Signature, &quot;1&quot;, 1, 3149, 1390, 3324, 1477);
              editor.AddField(FieldType.Signature, &quot;2&quot;, 1, 3164, 1302, 3309, 1389);
              // Save the form
              file = &quot;E:\\Temp\\1.pdf&quot;;
              editor.Save(file);
  
              for (int i = 1; i &lt; 3; i++)
              {
                  string signImageFile = &quot;&quot;;
                  PKCS7Detached pkcs = null;
                  PdfFileSignature pdfSign = new PdfFileSignature();
                  System.Drawing.Rectangle signRect = new System.Drawing.Rectangle();
  
                  if (i == 1)
                  {
                      pkcs = new PKCS7Detached(&quot;E:\\Sign\\1.p12&quot;, &quot;111111&quot;);
                      signImageFile = &quot;E:\\Sign\\1.png&quot;;
                      signRect = new System.Drawing.Rectangle(3149, 1390, 175, 87);
                  }
                  else if (i == 2)
                  {
                      pkcs = new PKCS7Detached(&quot;E:\\Sign\\2.p12&quot;, &quot;222222&quot;);
                      signImageFile = &quot;E:\\Sign\\2.png&quot;;
                      signRect = new System.Drawing.Rectangle(3164, 1302, 145, 87);
                  }
                  pkcs.ShowProperties = false;
  
                  pdfSign.BindPdf(file);
                  pdfSign.Sign(i.ToString(), &quot;&quot;, &quot;&quot;, &quot;&quot;, pkcs);
                  pdfSign.SignatureAppearance = signImageFile;
                  file = Path.Combine(&quot;E:\\Temp&quot;, (i + 1).ToString() + &quot;.pdf&quot;);
                  pdfSign.Save(file);
                  pdfSign.Close();
              }
          
  </code></pre>