6 Codes and Ciphers to Teach the Grandchildren

Many kids are fascinated by spy gear and gadgets, but the most important asset for a spy of any age is a working brain. Get the grandchildren interested in codes and ciphers, and they'll have fun while boosting their brain power. Sending coded messages is also a creative way for long-distance grandparents and grandchildren to stay in touch and bond.

  • 01 of 06

    Simple Substitutions

    Grandfather helping granddaughter solve a code or cipher
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    Most codes are actually ciphers. In codes, whole words are replaced by other whole words or symbols. In ciphers, letters are replaced by symbols, numbers or different letters. One simple substitution cipher replaces each letter with the one immediately after it in the alphabet. You can create a substitution slide or wheel that makes coding and decoding easy. In today's electronic age, the keyboard cipher is fun. Instead of typing a letter, use the letter to the left. If the desired letter is...MORE at the extreme left, "wrap around" and use the letter at the extreme right. Or come up with your own keyboard variation.

    Tips and Hints: Substitution ciphers are easy to use, but can be tedious for youngsters, since you are working with smaller pieces -- letters -- instead of words. Also, substitution codes are relatively easy to break by using word patterns and letter frequency. E, T, and A occur most frequently in the English language. I and A are the only single-letter words that are commonly used. It's fun to show the grandkids how to use information like this to solve a substitution cipher.

  • 02 of 06

    Book Codes

    If you and your grandchild have copies of the same book, you can create a code that will be hard for anyone else to crack. Dictionaries are often used, but any book with a good number of words in it will do. In the book, find the word that you want to use in your message. Turn it into a 7-digit number by using three digits for the page number, two digits to represent the line number and two digits to represent the position of the word in the line. Use zeroes to fill in any missing numerals.

    For...MORE example, to crack the code 0891104, you would go to page 89 and look at the fourth word in line 11. If you are using a book with columns, like many dictionaries, add a 1 or 2 after the page number to indicate the column.

    Tips and Hints: Book codes have the advantage of being relatively foolproof, but they can't be solved unless you have the book at hand. Also, if you are not using a dictionary, it can be difficult for children to find the word they need. On the other hand, book coding can promote flexibility in language as kids search for another way to say something.

  • 03 of 06

    Symbol Code or Cipher

    Using symbols, it is possible to create either a word-for-word code or a letter-by-letter cipher. For a symbol cipher, create a simple picture or symbol to represent each letter. Geometric figures, punctuation marks, smiley faces and other simple symbols are best. For a symbol code, do the same thing, but let each symbol represent a word. Obviously, you won't be able to create a symbol for every word, but actually, you don't have to code every word to create a secret message. Just code...MORE the most important ones for a kind of rebus effect.

    Tips and Hints: If your grandchild is patient and methodical, or artistic, he or she will enjoy this method. Others may find it frustrating. Also, in order to communicate, you'll both need a copy of the code key.

  • 04 of 06

    Date Shift Cipher

    Choose any easily remembered date, such as a grandchild's birthday. Turn it into an eight-digit numeral, using zeros if needed, as in the book code. Then write down the message you want to send. Directly under it, carefully write the eight-digit number, repeating it over and over. Be sure each letter has a number directly under it. To code your message, shift each letter alphabetically the number of spaces indicated by the number.

    For example, a D with a 3 under it would become a G. For...MORE letters near the end of the alphabet, you may have to wrap around to the beginning. To decode, do the same thing in reverse, shifting backward in the alphabet.

    Tips and Hints: Young children will be able to do the date shift cipher more easily if they write down the alphabet. The date shift cipher is not easily decoded because letters are not always replaced by exactly the same letter. Therefore, using letter frequency does not help.

    Continue to 5 of 6 below.
  • 05 of 06

    Route Cipher

    This is a cipher that works by reordering the letters. First, write down the desired message. Then, count the number of letters, not including spaces. Figure out what size grid will accommodate your message size. If you have 36 letters, for example, those letters can be put into a 4 X 9 grid or a 6 X 6 grid. You simply enter the letters in vertically and then create your message by copying the pattern horizontally, or vice versa. Since most messages are not going to be an easily factored number...MORE of letters, "null" letters are used to fill in any blank spaces at the end. For example, a message of 31 letters would need five nulls to fill out a 6 X 6 grid.

    Tips and Hints: You can use odd letters such as Q or J as null letters. More sophisticated coders use common letters because they are not easy to discern as null letters. Also, it's possible to vary directions and starting points within the grid to make it more difficult to solve.

  • 06 of 06

    Easy Codes

    If your grandchildren aren't quite old enough for the above codes and ciphers, you can still get them interested in codes by using these simple techniques:

    • Space-less Writing: Write your message without spaces, punctuation marks or capital letters. Beginning readers may find reading it quite challenging!
    • Backward writing: Write down your message; then copy it backward. Retain the spaces at first. Later try leaving out the spaces.
    • Scrambled Words: Write your message with a few of the words...MORE scrambled. As your grandchild improves at unscrambling, write it with all of the words scrambled.

    Tips and Hints Early school-age grandchildren will enjoy these codes. Keep messages very short and simple at first, and choose a time when the child isn't too tired.