Secret sharing
The dealer hands each player their part of the secret. In an easier setup, the parts of the players can be combined to form the secret, but with each part there is extra information. Say that a secret needs five parts, and three parts are known. In this setup, guessing the two parts that are missing will be easier than guessing the secret awhen no parts are known. The other setup is said to be secure from the point of view of information theory, because knowing part of the required number of player parts will not change how difficult it is to guess the secret.