You have to look at the procedures for moving against the publisher. Until someone actually reads the material, it isn't going to be a criminal matter. It would be like dumping shredded classified material. There is no crime there, until someone proves that they can piece it back together. Then you have published (distributed).

In the civil world, the issue would be one of harm. You aren't going to sustain a lawsuit unless you can state some harm. So long as nobody can read the encrypted material, there is no harm. But as soon as someone does you've got a case to bring.

There is an interesting statute of limitations question here as to when the clock starts, but that is a minor procedural issue imho. Many such statutes start not at the wrongdoing, but at the realization of the harm (or reasonable time of realization).