Tell me more ×  I am teaching students how to use Mathematica. I
want to create a problem set that has cells with a certain style
(probably Input or some new style that is a variant of Input)
locked down so that the students can not see them at all or just
see an unevaluatable placeholder instead. But I also want a cell
within the notebook that permits someone with a password (like
me) to make these hidden cells visible and evaluatable.  Extra
credit: it would be cool if I could relock these cells so that
they reverted to their hidden form.  Concession: Maybe the
unlocking cell does not have to be in the notebook but could be
a function in an external notebook that worked on the problem
set notebook.  Right now I accomplish the basic idea by having
two notebooks, one with the answers and one without them. But
this is ugly and leads to synchronization errors as I change my
mind.  Ideas welcome. Obviously, simpler is better.
share|improve this question Are your students knowledgable
enough to peek at the cell