US Patent 7246230 Single sign-on over the internet using public-key cryptography

A computer program product, apparatus, and method for use in an authentication server for obtaining access to a secure server for a client that has issued a request for access to the secure server, without further intervention by the user of the client, includes receiving an authentication challenge sent by the secure server to the client; and generating a ticket having a digital signature applied using a private key of the authentication server; and wherein the secure server, upon receiving the ticket and verifying the digital signature using a public key corresponding to the private key of the authentication server, grants access to the client.