The rules of discovery are very different in civil as opposed to criminal cases. In civil cases, you can only hide evidence up to a point, that is used for impeachment purposes, and then only from third party witnesses typically. The criminal case rules are totally different, and since I don't do criminal law, thank heavens, I cannot be of much help. But my vague impression, is that the prosecution does have to turn over much of its evidence beforehand, but not all, and I am not sure how the two categories are divided, and the defense does not have to turn over anything.
Thanks, I'm not a lawyer, but I have stayed at a Holiday Inn Express!