rootninja

Steganography is the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message.

From http://jerde.net/peter/cards/explanation.html

There are 8.06581752×10^67 unique ways to put 52 playing cards in order. By establishing a mathematical correspondence between an order of letters and the order of cards, we can hide a message in the deck of cards by simply putting them in the correct order.

If each card’s position is relative to the order of the cards, in this case from Clubs, Diamonds, Hearts, Spades, with each suit ordered from Deuce up to Ace - then the only thing missing to take this from an obscure message to a secure message is a password, or pre-shared key that serves as the agreed upon starting order of the deck.

Each card could be represented by two digits and a letter, 14S representing the Ace of Spades for example, and you append them end to end to determine the starting order of the deck. I know the key would be quite long, but I wonder how weak it’s cryptographic strength would be? Anyway, give it a try, here’s the encoding and decoding demo:

Encode a message:

Type a message and it puts the cards in order.
http://jerde.net/peter/cards/

Decode a message:

Click the cards in order to reveal a mesage.
http://jerde.net/peter/cards/decards.html