Digital Signatures in Form Integration 
When editing forms with security-sensitive content, it is a good idea to use digital signatures, so that the origin of the form can be verified. This allows you to check whether the source is trustworthy and whether the form or its content has been changed subsequently (integrity).
More information:
Prerequisites
Secure Adobe Document Services Connection
For the signatures, you need a secure connection using SSL or HTTPS. For this, your system needs an RFC connection of type HTTP Connection to External Server for the Adobe Document Services. The external server for the Adobe Document Services is the J2EE Engine.
Setting up a secure connection is described in Adobe Document Services Configuration Guide.
Documents with Signature Field
To set and check the signature, the form must have a signature field. You can insert this field in Form Builder (transaction SFP) in the Layout.
NoteIt does not make any difference whether the signature is server-side or client-side.
End of the note.
Signing a Form
Create a form with a signature field.
To digitally sign your form, click on the signature field.
(Example of Signature Field)Confirm the subsequent prompts.
The signature information is inserted in the signature field.
(Example of Signature)
Checking the Signature
The validity of the signature is checked by adding a Send button to the form. This button is then used to send the signed form back to the back end.
The method GET_SIGNATURES of the IF_FP_PDF_OBJECT interface is used.
More information: Scenarios for Setting and Checking Multiple Signatures.