Codes and ciphering
Jan. 16th, 2009 12:37 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
inferred_logicFrom The First Book of Codes and Ciphers by Sam and Beryl Epstein, published 1956.
Code is a method of writing in which each individual word is written as a secret code word, code number, or symbol. A cipher is a system of secret writing in which every letter, instead of every word, has a secret symbol.
for the word TROOPS use WHITE
for the word GUNS use GREEN
for the word CANNON use YELLOW
for the word BRIDGE use PURPLE
for the word ORDER use BLACK
for the word TO use PINK
An army commander who has a code like that could send out a message which says: BLACK WHITE YELLOW PINK PURPLE. And only another army officer would be able to understand that the message really says: order troops and cannon to bridge.
When George Washington set up a spy system during the American Revolution, his spies used a code for sending him information about the movements and strength of the enemy. These code books were made very simply. To make such a book, the man who invented the code sat down with a dictionary, and copied off into a notebook all the words a spy might have to use in his messages. Then he numbered the words in order.
War.....680
Was.....681
We......682
Will....683
With....684
A real code is very difficult to "break," as experts say. There are probably many codes used in the world today that have never been broken.
Here is a different kind of alphabet cipher. You make up a sentence using all 26 letters of the alphabet without repeating any. The order in which the letters in your sentence come will make your secret alphabet.
In the Bible there are several examples of the backward alphabet cipher. Ancient Hebrew prophets, thousands of years ago, used that cipher. There is one example in the book of Jeremiah, chapter 25, verse 26. One word of that verse is in cipher -- the word SHESHACH. It is a backward alphabet word for BABEL.
When you first look at those two words it may seem strange that a word of five letters can become a word of eight letters when it is put into the backward alphabet cipher. But the Hebrew alphabet is not like our alphabet. In Hebrew there is just one letter for our two letters SH, and one letter for our two letters CH. Calling their cipher ATHBASH was like calling our backward-alphabet cipher AZBY.
ABYZ --> 11-12-54-55
One of the famous code-makers of that time was Geronimo Cardano, who was born in Italy in the year 1501. He was an astrologer, a mathematician, and a fine doctor. Cardano invented what he called the Trellis Cipher. When he wished to write secret messages to a friend, he took two sheets of stiff paper and cut holes in each one. The holes in one sheet of paper were exactly the same size and in exactly the same position as the holes in the other sheet. Cardano then sent one trellis, as he called it, to his friend, and kept the other for himself.
When he wanted to write a message to his friend, he put his trellis over the clean sheet of paper, and wrote the secret message through the holes, putting one word in the top hole, one in the next lower one, and so on. Then he removed the trellis and filled up the rest of the paper with other words. This had to be done very carefully, of course, so that the secret words would fit into the rest of the writing and seem to make sense. Cardano said, "You must try to compose an innocent-looking message to fill in the gaps." When Cardano's friend received the message, he put his own trellis over the writing, and read just the few words that showed through the holes:
My dear Friend:
Have you heard the news? The King of Naples will soon make a visit to Rome. As for me, I prefer as usual to remain at home, especially now when it will soon be fine weather here. But I suppose it is necessary for the King to go, as Rome will not come to him.
The seeds in my garden are now all secretly swelling in the earth, and the swallows have arrived, so I know spring is close by. I hope your garden too does well, and that you enjoy good health by day and sound sleep by night.
G. Cardano
Another famous code-maker of the sixteenth century was Giambattista della Porta, an Italian scientist born in 1538. He wrote a book about secret codes, and has been called by some people the Father of Modern Cryptography.
Code is a method of writing in which each individual word is written as a secret code word, code number, or symbol. A cipher is a system of secret writing in which every letter, instead of every word, has a secret symbol.
for the word TROOPS use WHITE
for the word GUNS use GREEN
for the word CANNON use YELLOW
for the word BRIDGE use PURPLE
for the word ORDER use BLACK
for the word TO use PINK
An army commander who has a code like that could send out a message which says: BLACK WHITE YELLOW PINK PURPLE. And only another army officer would be able to understand that the message really says: order troops and cannon to bridge.
When George Washington set up a spy system during the American Revolution, his spies used a code for sending him information about the movements and strength of the enemy. These code books were made very simply. To make such a book, the man who invented the code sat down with a dictionary, and copied off into a notebook all the words a spy might have to use in his messages. Then he numbered the words in order.
War.....680
Was.....681
We......682
Will....683
With....684
A real code is very difficult to "break," as experts say. There are probably many codes used in the world today that have never been broken.
Here is a different kind of alphabet cipher. You make up a sentence using all 26 letters of the alphabet without repeating any. The order in which the letters in your sentence come will make your secret alphabet.
A B C DEFGH IJ KL M NOPQR STU V WXYZ V. F. X. BLITZ, JR., PH.D., KNOWS GUY Q. MACE
In the Bible there are several examples of the backward alphabet cipher. Ancient Hebrew prophets, thousands of years ago, used that cipher. There is one example in the book of Jeremiah, chapter 25, verse 26. One word of that verse is in cipher -- the word SHESHACH. It is a backward alphabet word for BABEL.
When you first look at those two words it may seem strange that a word of five letters can become a word of eight letters when it is put into the backward alphabet cipher. But the Hebrew alphabet is not like our alphabet. In Hebrew there is just one letter for our two letters SH, and one letter for our two letters CH. Calling their cipher ATHBASH was like calling our backward-alphabet cipher AZBY.
| 1 | 2 | 3 | 4 | 5 | |
| 1 | A | B | C | D | E |
| 2 | F | G | H | IJ | K |
| 3 | L | M | N | O | P |
| 4 | Q | R | S | T | U |
| 5 | V | W | X | Y | Z |
ABYZ --> 11-12-54-55
One of the famous code-makers of that time was Geronimo Cardano, who was born in Italy in the year 1501. He was an astrologer, a mathematician, and a fine doctor. Cardano invented what he called the Trellis Cipher. When he wished to write secret messages to a friend, he took two sheets of stiff paper and cut holes in each one. The holes in one sheet of paper were exactly the same size and in exactly the same position as the holes in the other sheet. Cardano then sent one trellis, as he called it, to his friend, and kept the other for himself.
When he wanted to write a message to his friend, he put his trellis over the clean sheet of paper, and wrote the secret message through the holes, putting one word in the top hole, one in the next lower one, and so on. Then he removed the trellis and filled up the rest of the paper with other words. This had to be done very carefully, of course, so that the secret words would fit into the rest of the writing and seem to make sense. Cardano said, "You must try to compose an innocent-looking message to fill in the gaps." When Cardano's friend received the message, he put his own trellis over the writing, and read just the few words that showed through the holes:
My dear Friend:
Have you heard the news? The King of Naples will soon make a visit to Rome. As for me, I prefer as usual to remain at home, especially now when it will soon be fine weather here. But I suppose it is necessary for the King to go, as Rome will not come to him.
The seeds in my garden are now all secretly swelling in the earth, and the swallows have arrived, so I know spring is close by. I hope your garden too does well, and that you enjoy good health by day and sound sleep by night.
G. Cardano
Another famous code-maker of the sixteenth century was Giambattista della Porta, an Italian scientist born in 1538. He wrote a book about secret codes, and has been called by some people the Father of Modern Cryptography.
