1.3.1 Terminology

The following list defines some common terms that are subsequently used in the manual.

Player: A player is an active participant in an electronic card game.

Observer: An observer is an passive party who watches the game.

Card: The term card means the electronic representation of a playing card.

Card Type: The card type is a nonnegative integer which corresponds to the pattern on the picture side of a real playing card. We assume here that such a natural encoding always exists.

Masking: Masking is a process which aim is to transform the card representation such that the input card and the result cannot be linked (except for trivial conclusions). Roughly speaking, masking is the (re-)encryption of a card representation such that the original card type is preserved.

Card Secret: The card secret contains all random values used in a masking operation. These values must be kept secret until the card is publicly revealed. Otherwise the corresponding output of the masking transformation is linkable and other players may learn the card type.

Open Card: An open card is a card whose type can be easily determined by all players and usually by observers as well.

Masked Card: A masked card (also known as face-down card) is a card whose type is unknown to a subset of players. It can be only revealed, if all players cooperate in a common computation of the type.

Private Card: A private card is a card whose type is only known to its owner. As long as the owner does not corporate the type of the private card stays hidden to all other players (except for trivial conclusions).

Stack: A stack is a not necessarily disjoint subset of the whole card deck.

Prover and Verifier: The prover is a player who shows some property to another party called verifier. For example, he wants to show that a masking operation was performed correctly, i.e., the card type is preserved by the transformation.