Hello,

is there a way to ascertain that the digital certificate sent by
someone was created by him/her? Let's say that Mr. A, who is a
colleague, creates a certificate, but forgets to e-mail it to me. Now,
Mr. B, who's an impostor, creates a certificate in Mr. A's name, and e-
mails it to me, pretending to be Mr. A. I then import the fake
certificate into Acrobat Reader 8. Next, Mr. B signs a PDF document
with a the Mr. A signature which he has created, and e-mails it to me.
How can I tell the document was signed by someone other than Mr. A,
although it bears his signature?

Many thanks.

phiroc