We have lots of secret charges in Denmark. Usually it is because there are more than one person involved and we don't want to tip anybody of.

Often the identity of the person involved is also secret, but that is to protected that person, in case he or she is innocent. Such orders are always removed when the person is found guilty (to my knowledge anyway).

I think charges have to be revealed when the actual proceedings start, and of course the defendant and their lawyers know.