The landscape of computing and datacommunications has obviously changeddramatically in the last twenty years. From a scene of monolithic, isolatedmainframes and fledgling testbed networks, we have come to a place wherecomputers are legion, found in corporations, homes, laps, and even palms.
Networks are now ubiquitous, with the Internet in particular growing atunfathomable rates.
In this new neighborhood, much is different, including newthreats to the security and integrity of the machines we now depend on. At the root of the problem lie the increasing complexity of computer softwareand networks and the relative simplicity of the creatures that use them. Operating systems and applications have grown much more complicated as the usesand users of computers multiply. The software is often so convoluted that it isnot possible to insure that all bugs and vulnerabilities are out. Networks haveexposed a new problem, where individual operating systems are secure, butinsufficiencies in the protocols that connect them allow the machines to becompromised.