Secret Warfare: The Battle of Codes & Ciphers by Bruce Norman

I recently finished reading the book Secret Warfare: The Battle of Codes & Ciphers by Bruce Norman.  It consists of 187 pages in 17 chapters.  The book used news accounts and anecdotes to tell the history of codes, ciphers, and intelligence work in general.  However, at least one-half of the book described techniques and historical narrative from the 20^th century (this book was written prior to 2000).

Cryptography was defined by the author as “the science of secret writing,” (p. 13).  It’s etymology is the Greek words kryptos (secret) and graphos (writing).  In practical terms, Norman explained, “cryptography is the art of sending messages in such a way that the real meaning is hidden from everyone but the sender and the subject.”

The cryptographer has two means by which he may accomplish his work: codes and ciphers. A code is a system of words that represents other words for secrecy and/or brevity.  A cipher is the same as a code, except, rather than operating at the level of whole words, ciphers work on single letters.  Then, there are two kinds of ciphers: transposition and substitution.  Transposition is a technique where the cryptographer, analyst, or spy “jumbles” the letters (i.e. “secret” becomes something like “resect”).  When the cryptographer uses substitution, letters are replaced with other letters, numbers, or symbols.  Finally, to build the most complex kind of cipher, the cryptographer may combine both transposition and substitution.

One of the first people to use cryptography to obtain knowledge for the battlefield was General Lysander of Sparta in 405 BCE.  Lysander had allied himself with the Persians as he fought Athens victoriously.  However, the Persians became envious of him and seemed poised to turn on him and attack Sparta.  Lysander felt he was in a bind.  A slave came with a message and Lysander read it.  Then, he asked for the slave’s belt.  Down the length of the slave’s belt was a string of meaningless letters.  He took a baton and wrapped the slave’s belt in a spiral around it, bringing the letters into alignment such that a message was revealed: The Persians were false and plotting against Lysander.  The general sailed against the Persians quickly and was victorious.

The obvious point of all of this work enciphering and deciphering is “to disguise the message in such a way that someone who has the code or knows the cipher can understand it whereas someone who does not know the secret, cannot,” (p. 14).

Julius Caesar wrote to Cicero using a substitution cipher.  Caesar would take his message and move every letter three places down the alphabet.  Today, this simple cipher would offer almost no security.  Adding a it of complexity, however, can yield a useful cipher system.  The following cipher is of Greek origin.  The letters of the alphabet are arranged into a square and numbers substituted for letters.  There are five columns by five rows, with the letters I and J put in the same placeholder.  It looks like this:

            1          2          3          4          5

1          L          B         O         S          F

2          E          V         U         G         R

3          X         A         M         C         Y

4          N         T          D         Z          K

5          W        H         I/J        Q         P

Thus, to encode the message “charge,” first write the number from the row, then the column.  So, for letter C, use 34. The full word/message: 34 52 32 25 24 21.  You can see that leaving the numbers with the same spacing, etc. makes the cipher vulnerable to being “cracked.”  Therefore, to confuse codebreakers coded messages are written in five-figure groups called code groups. Then, use zero (called nulls) to complete the five-figure group for ay remaining digits.  So, the previous message would be written:  34523 22524 21000.

Author Norman populated the text with numerous examples of codes and ciphers in various historical periods. One interesting example was from the Renaissance.  Abbot Trithemius, a Benedictine monk, wrote the first book on cryptography titled Polygraphia in 1518. Trithemius’s method was quite interesting to me.  It is a simple substitution cipher, but instead of using letters or other characters, each letter of the text to be enciphered is replaced by an entire word or phrase. There are several words or phrases for each letter and any can be used (from a pre-determined list).

Another interesting chapter discussed Captain Frederick Marryat’s development of a system of colored flags for naval signals which he called semaphore. It also discussed S.F.B. Morse’s electromagnetic telegraph and his famous alphabetic system of signals called “Morse Code.”  But perhaps my favorite cipher in the entire text was the “Pig-Pen Cipher,” which was used by Union prisoners held in Confederate prison camps during the Civil War.  With the Pig-Pen Cipher, the alphabet is written in a nine-cell diagram.

ABC	DEF	GHI
JKL	MNO	PQR
STU	VWX	YZ

Then each letter of your message indicated by drawing the section you are using plus one dot to indicate the second letter of the group, two dots to represent the third letter of the group, and no dots to indicate the first letter in the group.  Thus, the word “student” is given as:

___      ___      ___                              ____    ___

     |        * |      ** |      |___|     |_*_|     |_*_|       *  |

At least, that’s the best I can render for now.

This is just a small sample of the coding and ciphering techniques demonstrated in Norman’s book.  As I indicated earlier, it is a bit of an older book and I have several other books on codes and cryptography (some of which I may review here as I complete them). Secret Warfare is, on balance, well written and rich with historical context.  The chapters describing codes and code breaking activity during World War II are particularly enlightening.  It is amazing to realize the extent to which code breaking and code security contributed to outcomes on the battlefield.

As always, happy learning!