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Feature request: Lock form fields after signing


We’re planning to use Aspose PDF to prepare PDF documents for digital signing. PDF specification 1.5 supports using a ‘SigFieldLock’ dictionary on the signature field to prevent form fields from being edited after a document has been digitally signed.

I haven’t found a way to add the dictionary to the field myself, so it would be very useful for us if this feature could be implemented in the Aspose PDF library. Or is there another way to add this behaviour to the signature field using the current library?

See PDF Reference: https://online.flippingbook.com/view/415756/696/

I have a sample PDF document avaialble that uses this functionality. See attachment.

Best regards,


Lock form fields after signing example.pdf (72.5 KB)
Example without lock.pdf (75.8 KB)


Changing the content of a signed PDF document revokes the validity of signatures. Furthermore, we are afraid that the feature mentioned by you is not currently supported and we have logged a feature request as PDFNET-49183 in our issue tracking system for implementation. We will further investigate the feasibility of this feature and keep you posted with the status of its availability. Please be patient and spare us some time.

We are sorry for the inconvenience.