The world's largest conference dedicated to computer security opened its doors today at San Francisco's Moscone Center. Over 16,000 people are expected to show up. Among them, the CEOs of Computer Associates, EMC (the show's host), Oracle, Symantec, Verisign, WebSense and for the last time before he moves on fulltime to his foundation, Bill Gates of Microsoft. This year the conference celebrates the influence of 15th century Renaissance man Leon Battista Alberti, "the Father of Western Cryptology" and creator of the polyalphabetic cipher in 1466.