Hello, remember what ciphers are? Well, there are 2 kinds of ciphers. One of them is the substitution cipher. A substitution literally substitutes one letter/symbol for another letter/symbol. The transition cipher takes the letters in the message and scrambles them. This is still a cipher because it uses letters/symbols and changes them. The first substitution cipher you will learn is the Date Shift Cipher.
Date Shift Cipher Preparation: You and your partner will need to decide on a date. It could be the actual date, or a date in history. Whatever you choose, the date is very important, so do not forget it! You will also need plenty of paper besides the one you are writing the message on. Difficulty to Use: This cipher will require you to write out the alphabet, and will take some time to encipher and decipher. Difficulty to Crack: This is almost impossible to crack unless you know a lot about this cipher, or else you know the date. It is very secure.
The Cipher: This is a very fun cipher to use.
To Encipher: First choose your date. We will use the random date 01/17/99. Write out your message like this: P l e a s e c o m e a n d h u r r y ! Over top, write the date over and over, without the slashes, like this:
0 1 1 7 9 9 0 1 1 7 9 9 0 1 1 7 99 0
P l e a s e c o m e a n d h u r r y !
Next move each letter the number of places in the alphabet as the number over it. In the example, you would move P zero spaces, but would move the second e in please nine spaces.
To Decipher: We will use the same example for the deciphering part. When you get the message, write it out with the date over top as you did above. You will decipher the same way that you enciphered, except you will move that number of places back in the alphabet.
Keyboard Cipher Preparation: You and your partner will need a keyboard, or else you will need to be able to picture one in your mind. Difficulty to Use: This is not a very difficult cipher to use. It is easy to encipher and to decipher as long as you are familiar with keyboards. Difficulty to Crack: This is a fairly easy cipher to crack if you take the time to write out a frequency list. The Keyboard Cipher makes up for its lack of security in the fact that it is quick and easy to write.
The Cipher: It is helpful to write out the message in plaintext on a separate piece of paper, but it is not necessary.
To Encipher: Let's use the message "Meeting at 9:00 am Tuesday." The first letter in the message is M. To encipher, look at the keyboard and write down the letter immediately to the left of M. This letter happens to be n. Finish writing the message like this. If you get to the end of the row, then wrap around to the beginning. In this case, a would be l.
To Decipher: Follow the same procedure as when enciphering, except move the letter to the right.
Caesar Cipher Preparation: You will need to write the alphabet out. Difficulty to Use: This can take some time until you practice more often and become faster. Other than that, it is not an extremely hard cipher. Difficulty to Crack: The Caesar Cipher is a very famous and well known cipher. Most snoopers will try the Caesar Cipher and its variants right away, but if you vary the cipher slightly it will decrease the chance that your message will be discovered.
The Cipher: This cipher was invented by Augustus Caesar himself, who used it during battles to hid secret information.
To Encipher: Write out the alphabet. When that is done, write out the plain text message. This will be very useful as you encipher. Now, we will use the message "Come quickly." To encipher, take the first letter in the message, c, and move it 3 places in the alphabet. This means c equals f. Continue with the rest of the message in the same way. You and your partner can decide on a different number as a variant, but the number 3 is the original.
To Decipher: Use the same procedure as when you encipher, except shift backwards. Remember to wrap around!
Dot Cipher Preparation: You will need graph paper, and a sharp pencil. A ruler is also helpful. Difficulty to Use: This cipher is not hard to use, but it is extremely helpful to have a ruler or other strait edge. Difficulty to Crack: This cipher will look like a series of meaningless dots to any snooper.
The Cipher: This cipher is a very good cipher to use. Any snooper will just look at it, and then probably get rid of it.
To Encipher: On the top of one piece of graph paper, write the alphabet on the lines. This is very important. Lay the other piece of graph paper on top of the paper, and be sure to line it up. Suppose the message is "Need help. Come quickly." Find N on the top of the one piece of paper. Use the ruler and follow the line on the other paper in the same location. When you come to the first horizontal line intersecting it, mark a dot at the place where they meet. Use the same procedure for the letter e, but mark it one horizontal line below the other dot. Continue in this way, moving down the page.
To Decipher: Follow the same procedure, except go up. It is helpful to write down the message on another piece of paper as you go, and to cross out the dots you have already deciphered to prevent confusion.