What are you trying to authenticate to? What you are describing sounds
like "client authentication" when establishing a TLS\SSL connection to a
server. Check out wikipedia for details
http://en.wikipedia.org/wiki/Transport_Layer_Security (see the
Client-authenticated TLS handshake section).When using Digital
Certificates to create a digital signature, the certificate is tied to a
specific user (not a particular machine) Check out
http://en.wikipedia.org/wiki/Digital_certificates for more
details...