title: How to enable LTV for a timestamp signature and set the pdf change not allowed?
body: <p>I am signing a pdf with digital certificate using <code>iText</code>. Now I can sign, and add LTV, but CertificateLevel can just be:</p>
  
  <pre class="lang-java prettyprint-override"><code>signatureAppearance.setCertificationLevel(PdfSignatureAppearance.CERTIFIED_FORM_FILLING_AND_ANNOTATIONS);
  </code></pre>
  
  <p>I just want to set <code>PdfSignatureAppearance.CERTIFIED_NO_CHANGES_ALLOWED</code>. The final result should look like this:</p>
  
  <p><a href="https://i.stack.imgur.com/ZWvif.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZWvif.png" alt="enter image description here"></a></p>
  
  <pre class="lang-java prettyprint-override"><code>sap.setCertificationLevel(PdfSignatureAppearance.CERTIFIED_NO_CHANGES_ALLOWED);
  MakeSignature.signDetached(signatureAppearance, privateKey, "SHA-512", chain, null, ocspClient, tsaClient, 0, MakeSignature.CryptoStandard.CADES);
  </code></pre>
  
  <p>If i use the above code to sign, then using AdobeLtvEnabling.java to add LTV will prompt the signature to be invalid when using ACROBAT check, because the file is modifying the unmodifiable PDF file when adding LTV. Thus, what can i do to approach the final effect.</p>