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LC Designer dynamic form invalidate signature on re-opening


Level 1

Dear all,

We have a dynamic pdf form developed using LC Designer ES4 distributed to user for form filling.

The form performs heavy formatting or rendering based on data filled by client by making some pages hidden or visible,

create new rows or instances on subform tables, adding continuous pages if necessary and etc.

After data verification, the final formatted pages or look is/are then printed out by client and return to us with the hardcopy.

Now we want to enhance the form by adding a signature field on the final formatted pages or look.

Then client will sign and return the saved softcopy to us by uploading to our server. 

But on testing, after we sign the form (which automatically prompts to save the pdf) on the same workstation and then

re-open it, the signature becomes invalid because on form loading, a lot of formatting or rendering has to be performed

to recover to the state when the form is signed, but still Reader complains that the content for some fields have been changed

which cause the signature to become invalid.

Any idea?


2 Replies


Level 3

If the purpose of your digital signature is to protect and assure the information in certain specific fields, then try to us the "lock fields after signing" option.

that would make sure that your digital signature is mainly concentrating on specific fields only, and even if there's a script which runs at Form Ready/ Initialize or other such events, those scripts should not touch these fields which are signed already.


Level 1


Thanks for your reply.

Since the signature field is intend to validate the authenticity and integrity of the pdf, so the lock has to apply to the whole form.

I tried by selecting the option of preserving form state automatically in the form properties which can preserve the state after I open again,

but the manual stated that if the form is certified, we must manually preserve the form state, dunno why.