Is reverse engineering always legal?

Reverse engineering-the process of looking at lower levels of abstraction to understand higher levels-is not limited to decompiling programs, as many believe. It is an excellent way to pinpoint what you need to build an interface or change a system to reflect new business goals. But unraveling someone's code opens up a legal can of worms, and as reverse engineering becomes more popular, some people are taking time out from their Y2K worries to say, "is this legal?" This in and of itself is not new-the law seems consistently to be an afterthought to solving technological problems-but in this case, the current preoccupation with reverse engineering may cause the two disciplines to finally stop and consider each other. The courts may realize that if we want to achieve a global electronic society, the law has to make it easier for systems to become interoperable, correct, and secure. Software and system developers may realize that long-standing legal principles can actually work for them, not tie their hands and, more important, that they can influence the laws being made. Unfortunately, we seem to be taking one step forward and two steps back in trying to make this happen. Laws in four key regions-the US, EU, Japan, and Australia-reveal foundational inconsistencies in attitudes about reverse engineering. And recent US legislation, both enacted and proposed, is conflicted.