|You are getting "A" Digital Signature? I think you may be confused by what exactly a Digital Signature is. Digital Signatures are user specific, which means that each user that wants to digitally sign information must have his/her own Private key. Along with that is the password that each user enters in order to Digitally sign emails/documents, etc.|
Or, might you be referring to an Electronic Signature, which is another ball of wax. :)
A Public Key is then needed in order for others to view that Digitally signed information.
I think you need to do some research on Digital (Identity) Signatures/Certificates and Encryption Certificates, which work together with a Digital Signature, but are a separate entity.