This paper presents a type of verification technique that securely protects access to any restricted material by showing different random challenge on each access attempt. Each challenge generates a ...

* While many believe that a challenge/response mechanism imposes an undue burden on new e-mail senders, this is actually just a myth, since the average user would challenge a legitimate sender only ...

A new e-mail service aims to put an end to unsolicited commercial (“spam”) e-mail by collecting the addresses of legitimate e-mail senders on to a master list that will take the “challenge” out of ...

An authentication method that proves the identity of users logging into a network. When a user logs in, the access server or authentication server sends a random number (the challenge) to the client.