Comment by mehrdadn

It is commonly messed up, and I'm not claiming it's easy by any means, although a lot of pitfalls are just because some ciphers are a lot worse than others in being able to get right. But what I mean is that the difficulty of asymmetric crypto is in a very different league IMO. The kinds of pitfalls that are in symmetric crypto (with the better ciphers at least) tend to be pretty understandable for non-experts (regardless of how obvious they are a priori). Whereas with asymmetric crypto it seems like a PhD in number theory (or similar) is more or less a prerequisite.