Thanks for the reply.
>If you're using email to send the forms around, you have to use Restricted.
I set up Certificate services server as this link:
http://marcellotonarelli.wordpress.com/2009/10/28/domain-certificate-authority-signing-infopath-2007-forms/ (use code signing template)
The form xsn is configured to allow co-sign (multiple users can sign)
We asked two internal users (only for domain internal userA and userB) to digitally signed and it can not validate signature
each other. We do not have sharepoint server and users use InfoPath filler to open it. Users A signs the form and digitally signed and then send the form to user B through email
When userB opens the form (attachment) in Outlook (every user has InfoPath installed), userB can not see the userA certificate info and the message shows "the signature is not valid"
these certificates are issued by our internal CA and our Certificate server is in everyone's trusted root certificate store
(details: userA requested the cert from our internal CA and install it and appears in the user personal certificate store; then digitally sign the form by using his certificate; email the
signed form to user B. User B open the form and got" the signature is not valid".
What am I missing? why do internal users can not validate signatures each other with our internal certificate server?
Thank you for your help.