Digital Signature

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   Hi, my application is in C/C++ for Windows platform & I want to use Quick PDF library to 
generate multi-lingual PDFs that are digitally signed using one of the certificates on system.

I'm unable to get any documentation on how would one use Quick PDF library to digitally sign a PDF using a certificate from store. All I've got until now is SetSignProcessCertFromStore method from the documents, but there is no sample code on how do I go about using it.

Any documentation or samples or guide on this would be really helpful.

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
DigitalSignature Members Profile Find Members Posts Beginner Joined: 20 Jan 21 Status: Offline Points: 12	Post Options Post Reply Quote DigitalSignature Report Post Thanks(0) Quote Reply Topic: Digital Signature Posted: 20 Jan 21 at 8:40AM
	Hi, my application is in C/C++ for Windows platform & I want to use Quick PDF library to generate multi-lingual PDFs that are digitally signed using one of the certificates on system. I'm unable to get any documentation on how would one use Quick PDF library to digitally sign a PDF using a certificate from store. All I've got until now is SetSignProcessCertFromStore method from the documents, but there is no sample code on how do I go about using it. Any documentation or samples or guide on this would be really helpful.

tfrost Members Profile Find Members Posts Senior Member Joined: 06 Sep 10 Location: UK Status: Offline Points: 437	Post Options Post Reply Quote tfrost Report Post Thanks(1) Quote Reply Posted: 20 Jan 21 at 1:34PM
	I have not used a certificate from the Windows store, but I have used a certificate from a PFX file. Basically you start a Sign Process with qp.NewSignProcessFromX, where X is 'file' or 'stream' or 'string' containing the PDF. This function returns a sign process ID which is required in all subsequent signing calls. Then if you want a picture stamp, you may need to use SetSignProcessField, SetSignProcessFieldBounds, SetSignProcessFieldImageFromFile, and then you may need QP.SetNeedAppearances(0). Next, SetSignProcessSubFilter and SetSignProcessInfo if you need them. Finally I use SetSignProcessPFXFromFile to load the certificate, but you would replace this with SetSignProcessCertFromStore. To save the signed PDF you call EndSignProcessToFile(id, outputpdffile) and qp.GetSignProcessResult. Make sure that you use a certificate which supports PDF-signing. Not all do. And it is essential to check, report and fix any error returns from the above functions, before continuing to the next one. It does all work, but there is a lot to get right. Persevere!

DigitalSignature Members Profile Find Members Posts Beginner Joined: 20 Jan 21 Status: Offline Points: 12	Post Options Post Reply Quote DigitalSignature Report Post Thanks(0) Quote Reply Posted: 21 Jan 21 at 4:21AM
	@tfrost That was really helpful, thank you. Will try this out and get back if I run into any issue.

DigitalSignature Members Profile Find Members Posts Beginner Joined: 20 Jan 21 Status: Offline Points: 12	Post Options Post Reply Quote DigitalSignature Report Post Thanks(1) Quote Reply Posted: 28 Jan 21 at 1:21PM
	@tfrost It worked! Thanks a lot. For others who would have a similar requirement to sign PDF using windows store certificate the process is as follows : 1) Start a signing intent with NewSignProcessFromXXX & use SignProcessID returned by this method on all API calls below 2) Get SHA1 hash of the certificate and call SetSignProcessCertFromStore 3) Specify signature field on PDF using SetSignProcessField, if you don't have one, it'll create it for you 4) Call EndSignProcessToXXX to sign PDF 5) GetSignProcessResult can be used to verify if PDF was signed successfully

mLipok Members Profile Find Members Posts Senior Member Joined: 23 Apr 14 Location: Poland, Zabrze Status: Offline Points: 453	Post Options Post Reply Quote mLipok Report Post Thanks(0) Quote Reply Posted: 23 Feb 21 at 11:36PM
	maybe here: https://developers.foxitsoftware.com/kb/article/advanced-options-signing-pdf-files/ btw. Somebody can provide how to modify this example to use CryptCards ?
	Here you can find description how to test my examples: http://www.quickpdf.org/forum/forum_posts.asp?TID=2932&PID=12600&title=drawcapturedpagematrix-matrix-howto#12600