Example: Alice has picked cards 1 to 5 in the shuffled deck. Bob has picked cards 6 to 10. Bob requests to look at his allotted cards. Alice agrees that Bob is entitled to look at cards 6 to 10 and gives him her individual card keys A6 to A10. Bob decrypts his cards by using both Alice's keys and his own for these cards, B6 to B10. Bob can now see the cards. Alice cannot know which cards Bob has because she does not have access to Bob's keys B6 to B10 which are required to decrypt the cards.