[Defense and government networks are hardening their security, but for regular users, the best strategy against high-tech crime can be simple.] Our best defenses against these kind of attacks are often of a low tech variety -- that is, keep paper records of your transactions, ... Even though much of what we have exists only as a series of ones and zeroes somewhere in the information sphere, we do get paper copies and we should hang on to those. The movie 'The Net,' I think, makes a very intriguing point, about this very computer literate protagonist who has few human connections, and this is precisely the reason she's vulnerable to the kind of attack she suffers. It seems to me that if we keep that in mind we'll be well served.
