The intruder's attack on the WELL and other computer systems on the Internet required only a modicum of skill to execute. The techniques that were used to break into these systems are well known to computer security experts and anyone else with an interest in such things. It's a good bet that there are others with the skills and knowledge required to repeat this mischief. The simple fact is that the open nature of the computer technology that has fostered the remarkable growth of the Internet also makes it vulnerable. When everyone knows how the technology works, it's easy to use and to build upon, and it's also easy to subvert.
Openness is a double- edged sword.
Secrecy tends to impede technological development, and in the long run it simply doesn't work. Secrets never remain so for long and again Mitnick helps prove the point. His ability to manipulate the public telephone system has been well documented, despite the fact that telephone companies don't widely disseminate their sensitive technical information. Unsecurable, that is, unless we consider something called cryptography. Once strictly the province of spies, government security agencies and the military, cryptography has seen increasing use in sensitive commercial applications such as electronic funds transfer in banking.