solitaire-encryption

Repository of side project experimenting with solitaire encryption.

This project is intended as an opportunity to experiment with the solitaire encryption algorithm. An in depth description of this algorithm can be found here: https://en.wikipedia.org/wiki/Solitaire_(cipher).

A default Deck of Cards when in order will be: A-K, CDaHbS; a = JokerA, b = JokerB. Each card has a value which is used when encrypting/decrypting an input:

• C (Clubs): 1-13
• D (Diamonds): 14-26
• H (Hearts): 27-39
• S (Spades): 40-52
• Jokers: 53
• Each letter has a value given its position in the alphabet: A-Z = 1-26

The steps of the algorithm in question are:

1. Move Joker A down 1 card.
2. Move Joker B down 2 cards.
3. Triple cut: switch the cards before the 1st joker with those after the 2nd joker.
4. Count Cut: look at the bottom card, count down from the top of the deck that many cards. Cut after the card you counted to. Keep the bottom card the same.
5. Look at the top card, and count down that many cards from the top. If you hit a joker, start with step 1 again. Otherwise, that is the newest value for the Key.
6. Append that value to the Key and restart from step 1 for as many times as needed. The end goal will be to have a Key with the same number of values as the length of the input phrase.

Encryption Steps:

1. Step through the input phrase and the Key in parallel.
2. Add the value of the Key to the character in question and then mod the sum by 26.
3. Append the new character to the output string.
4. Repeat steps 1-3 for the entire length of the input phrase and then return the now encrypted output.

Decryption Steps:

1. Step through the input phrase and the Key in parallel.
2. Substract the value of the Key from the character in question and then mod the result by 26.
3. Append the new character to the output string.
4. Repeat steps 1-3 for the entire length of the input phrase and then return the now decrypted output.

How to run this program:

There are two ways to run this program:

1. Check out the code and import it into an IDE (such as Eclipse). From there you can run the Execute.java file to interact with the Command Line Interface within your IDE.
2. Check out the code and build it into a runnable jar with Execute.java as the main class. From there you can run the jar in an environment of your choice and interact with the same Command Line Interface.

Command Line Interface (CLI) Options:

After running the program you will be faced with a few options:

1. "Enter phrase:" - Enter whatever phrase you want encrypted/decrypted by the program.
2. "Enter e for encryption, enter d for decryption:" - Enter whether you want to encrypt or decrypt the provided phrase.
3. "Enter o for an ordered deck, enter r for a random deck, enter s to specify your own deck:" - Enter whether you want it to use a deck in numberical order (primarily for testing), a random ordering (primarily for encryption), or to specify your own deck ordering (primarily for decryption).
4. [If you selected 's' to specify your own deck] "Enter order for your deck (Ex: [C1,C2,...,JA53,...D17,...JB53,S48]:" - Enter the 54 card sequence you want the program to use to encrypt/decrypt the message.

The program will then run the appropriate encryption/decryption and return the output to you on the command line. If you selected 'r' for it to use a random deck, it will also return the deck it generated to do the encryption/decryption. This deck can be saved and used later on to encrypt/decrypt the same message again (i.e. to get the plain text version of an encrypted phrase again).