Securing pdf document with digital signatures

Question

I have a pdf document that has digital signatures. We need to secure it so no one who has input their digital signature can go back in later, delete their signature and then 're-sign' it. But I get an error message telling me I can't secure the document because it has digital signatures.
Is there any way to secure the document so only I can secure/unsecure it after digital signatures have been input?
Thanks!

Answer 1

You don't need to use document encryption to lock the PDF file. You can set the signature field properties to mark all fields as read-only at signature creation. Try this:
Select the Tools > Toolbars > Advanced Editing menu item
Click the Select Object tool on the Advanced editing toolbar (it's the arrow icon)
Right mouse click on the signature field and select Properties from the pop-up menu
Select the Signed tab on the Digital Signature Properties dialog
Select the Mark as read-only radio button and All fields from the corresponding drop-down list
Click the Close button on the Digital Signature Properties dialog
Select the File > Save As menu item and save a copy (in other words, leave the original copy as is in case you find you locked yourself out of the document, that way you'll have a fall-back recovery option)
Good luck,
Steve