Re: Applying Digital Signatures on PDF Documents on iOS

[Support]

 

FYI: The current version of PDFNet includes high-level signature API. For more info please see:

   https://groups.google.com/d/topic/pdfnet-sdk/SGcTSYFjaSk/discussion

 

 

 

On Thursday, July 26, 2012 1:55:26 PM UTC-7, Qamar Suleiman wrote:

Hi Vincent,

Thanks for your generous reply. Could you please tell me how could I do do that

"

// now that the document is serialized, calculate the signature by the reading the bytes specified by the /ByteRange, then write this signature in
// the /Contents entry.

"

I would really appreciate if you could put some code in here, especially if its C or Objective C Code

Thanks,

Qamar

On Thursday, July 26, 2012 2:29:57 PM UTC-4, Vincent Ycasas wrote:

Using PDFNet, you can add digital signatures to an existing signature field by using the low-level COS/SDF API. The following code snippet describes this process:

Field sigFld = doc.GetField(UString("mysigfield"));
// create a signature dictionary and assign this dictionary as sigFld's value
SDF::Obj sigDict = doc.CreateIndirectDict();
// add the needed information in the sigDict like ByteRange, Filter, etc.
sigDict.PutName("Type", "Sig");
sigDict.PutName("Filter", "MyFilter");
SDF::Obj byteRange = sigDict.PutArray("ByteRange");
// add the required byte ranges to the byteRange Array
sigDict.PutString("Contents", "0000"); // it will be necessary to put enough space in the contents field so that the final signature calculated will fit.
sigFld.SetValue(sigDict);
// save the PDFDoc
doc.Save(...);
// now that the document is serialized, calculate the signature by the reading the bytes specified by the /ByteRange, then write this signature in
// the /Contents entry.

We will be adding digital signatures API for the next major update of PDFNet. Please keep checking the website for news and update.