The problem There are many aspects to privacy in electronic information.
Cryptography solves some of the problems as far as transmitted information is concerned.
Stored information involves problems of a different nature. Two of these categories of problems are discussed below, but this discussion is by no means complete. The following discussion deals mainly with Windows NT, the only system with which I have extensive experience. Much of this information is applicable to other systems, but I cannot tell you to what extent. I cannot be very precise on some of the points, because the technologies continue to improve.