How can I add document signatures to a dynamic table using Adobe LiveCycle?

Question

I have a table where I am adding rows dynamically by adding a + or - button to add or remove rows to add to the table.

Right now I have a name field and an e-sign field. The problem I am having is that the document signature cannot be repeatable/ needs to be unique and so cannot be added to a dynamic table? Is there a work around for this?

Ultimately what I want is to have a PDF form look like below:

+ -
First Name | Last Name | Signature
First Name |  Last Name | Signature

When the user clicks on + from the form above, then it just adds a new row like:

+ -
First Name | Last Name | Signature
First Name |  Last Name | Signature
First Name |  Last Name | Signature

Problem is the e-signature is a new instance and it says it cannot be repeatable? I want these to be different signatures but on one form to be added dynamically. Does this make sense? How can I do this?

Answer 1

Unfortunately, digital signatures and dynamic forms are generally speaking incompatible. When a PDF is signed, a hash of the PDF is taken and then signed with the signer’s certificate. This ensures that any changes to the PDF will invalidate the signature.

Dynamic PDFs essentially re-build the PDF from the XDP form definition each time the form is loaded and/or each time the form changes. This causes any digital signatures to become invalid.

Now there are ways to accomplish a level of dynamic behaviour in a form that will be signed. Dynamic XDPs can be rendered as static PDFs on the server. Since they are static when they arrive on the client, they can be signed.

This approach requires that you know how many signature fields are required before the PDF is rendered. The most common approach is to perform multiple renderings on the server, as follows:

1. Generate a dynamic PDF that captures all the data that is required in the form (including the number of signatures the form requires). One approach to capturing the number of signatures required could be using a dynamic table to add rows that contain a read-only signature field.
2. Use the dynamic PDF to capture all the data and then submit that data back to the server.
3. Generate a static PDF by merging the submitted data with the XDP on the server. The static version is the version to be signed. On this version, the dynamic table’s add/remove buttons are hidden and all fields except for the signatures are read-only. The signature fields on this version are marked as “open”.
4. The user(s) can now sign the signature fields as they would any other static PDF.

You control whether a form is rendered as dynamic or static by either the RenderAtClient flag on the server or the PDF Render Format in the form properties in LiveCycle Designer.