How to Certify (not sign) a PDF

Question

Hi,I'm new to Syncfusion so go easy :-)  Very simply, I'm trying to replicate the "Certify (invisible signature)" functionality within Acrobat Pro.  This is different to digitally signing the document.  I've been through the documentation and reviewed the Working with Digital Signature functions and have been able to sign a form but not just certify it.  Is certifying using Syncfusion PDF possible?  The image below shows the difference in the signature panel of a certified vs signed document.Thanks.

Sowmiya Loganathan · Answer

Hi Gordon,    
  
Thank you for contacting Syncfusion support.    
  
We have analyzed your requirement “Certify (invisible signature) PDF document as like Acrobat Pro” and we can achieve this by using Certificated property of PdfSignature. Please refer the below documentation for more details,    
  
KB: https://www.syncfusion.com/kb/11168/how-to-sign-a-pdf-document-without-showing-the-signature    
  
Please let us know if you need any further assistance on this.    
   
Regards, 
Sowmiya Loganathan

Gordon · Answer

Thank you for your assistance which pointed me in the right direction. To certify a document without adding an actual signature (as your example offered), can be accomplished as follows :-

PdfLoadedDocument document = new PdfLoadedDocument(infile);

PdfLoadedPage page = document.Pages[0] as PdfLoadedPage;

PdfCertificate pdfCert = new PdfCertificate(cert,pass);

PdfSignature signature = new PdfSignature(document, page, pdfCert, "Signature");

signature.Certificated = true;

document.Save(outfile);

document.Close(true);

This resulted in no signature field actually being added, but the PDF itself was correctly certified.

Thanks again for your help.

Gordon.

Sowmiya Loganathan · Answer

Hi Gordon,   
 
We have created the sample to sign an existing PDF document without showing the signature. Please find the download link from below,   
 
Sample: https://www.syncfusion.com/downloads/support/forum/162570/ze/DigitalSignature_Sample-691885903   
Output document: https://www.syncfusion.com/downloads/support/forum/162570/pd/Sample880341286   
 
Could you please try the above sample in your end and let us know the result. If you still facing any issue, please provide us the below details. It will helpful for us to provide the precise solution on this.   

Modified sample
Input PDF document 
 
Regards,  
Sowmiya Loganathan