[ Thanks to zanek for this
link. ]
“Digital signatures were designed to allow secure, confidential
communication between two parties.“As Wikipedia describes it: ‘A user may digitally sign messages
using his private key, and another user can check that signature
(using the public key contained in that user’s certificate issued
by a certificate authority). This enables two (or more)
communicating parties to establish confidentiality, message
integrity and user authentication without having to exchange any
secret information in advance…'”