title: How to sign a PDF file in Delphi with an Smart Card Certificate
body: <p>First, sorry for my english, this is not my first language, but let's go:</p>
  
  <p>I need to digital sign pdf documents in my software, but my client just have A3 certificates (with smart card).</p>
  
  <p>The problem here is that kind of certificates can't export PFX file which are required for signature in Debenu SDK or Gnostice for example.
  I've already been able to list and load the certificate using CAPICOM, but I do not know which library to use to sign the file, and how to do that without the PFX file.</p>
  
  <p>It is important that the file remains PDF after the signature.</p>