Nos operamur, te ludere
"Life is more fun if you play games." - Roald Dahl
I'm assuming that the nature of the game makes it inconvenient for the players to hold this information in-hand?
You could have stands for the cards so that they are vertical, facing the owner. When it's revealed lay the card down, face-up. When the new, hidden info is available, put that in the stand.
This is what I was going to say -- stands to hold the cards up when the information is secret, and you can then take the cards out and lay them face up on the table when they're not secret any more.