I live with two aspiring secret agents, who sometimes need to send important cryptic messages to each other. In addition to experimenting with lemon juice as invisible ink, weve been having loads of fun trying out various secret codes and ciphers. And as a bonus, playing with secret codes is a great way to sneak some writing into your summer days! here are three of our favorites to try with your mini detectives: secret code 1: reverse alphabet heres a simple reverse alphabet code to start with. Write the alphabet on your paper, then write it backwards directly underneath your letters.

To write your message, look at the top orange letters and write the bottom blue letters. To decipher it, find the letters on the bottom line, and write the corresponding letters from the top line. My girls loved the pig pen symbol code once they had some time to practice with it. Each letter is represented by the lines around it, and the second letter in each space also gets a dot. For example, a looks like a backwards l, and b looks the same but with a dot added. We practiced writing our names and silly words before moving to coding whole sentences.

The messages you write with the pig pen code look very sneaky and secret! a grid secret code is easy to set up, and is great practice for using coordinates, too. Two letters have to share a space i chose i and j, since they would not be easily confused in a word. We found that grid codes take a little extra time to write, but are quick to solve. we like leaving secret code notes for each other in unusual places the bathroom mirror, under a pillow, in the freezer, at the bottom of the slide.

I also use them to surprise the girls with spur of the moment park outings or ice cream dates. another fun way to play with codes is to set up a scavenger hunt. this takes a little bit more planning and time, but is a great way to spend a hot afternoon inside. Or perhaps you remember using special symbols to write notes to your squeeze in class. In more serious uses, codes and ciphers are used by our military and diplomatic forces to keep confidential information from unauthorized eyes. Businesses also send data that has been encoded to try and protect trade secrets and back room deals.

After all, you wouldn't want your competitor to know that you were about to acquire their company with a leveraged buy out. The study of enciphering and encoding on the sending end , and deciphering and decoding on the receiving end is called cryptography from the greek kryptos , or hidden and graphia , or writing. If you don't know greek and not many of us do the above letters could be a form of code themselves! although the distinction is fuzzy, ciphers are different from codes. When you substitute one word for another word or sentence, like using a foreign language dictionary, you are using a code. I told you the difference was fuzzy, and you can combine codes and ciphers by substituting one word for another and then mixing up the result. For a cipher to be useful, several things must be known at both the sending and receiving ends.

algorithm

method

key

by way of analogy, to get into your home you would put a key in a lock to open the door. Now this method only works if you have the proper key to stick in the lock, and your key will be valid only as long as you are the resident of the particular abode. The next resident will have the locks changed to a different key to make sure that you cannot enter even though you may know the method. The selection of the above three items algorithm, key and period depend on your needs. If you are in the battlefield and are receiving current tactical data, you want an algorithm that makes it easy to decipher the message in the heat of battle.

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On the other hand, you must also assume that your opponent has intercepted your enciphered message and is busy trying to break it. Therefore you must choose an algorithm method that is complicated enough so that by the time your opponent figures it out, the data will be worthless. The easier the algorithm you choose, the more often you will have to change the key that unlocks the code if you want to keep your enemy in the dark. Ciphers are broken into two main categories substitution ciphers and transposition ciphers. Substitution ciphers replace letters in the plaintext with other letters or symbols, keeping the order in which the symbols fall the same. Transposition ciphers keep all of the original letters intact, but mix up their order. Of course, you can use both methods, one after the other, to further confuse an unintended receiver as well.