Codes and Ciphers

by Sean Callery

From the history of codemaking to practical examples and tips for cracking your own codes, "Need to Know? - Codes and Ciphers" covers everything you have ever wanted to know about this area in a clear and easy to understand way. Why do we use codes? Why do we need them? From the moment we began communicating, we have looked for ways to make our messages concise and clear; but with the advent of wars and trading, it has been necessary to find ways to keep some of that communication secret. "Need to Know? - Codes and Ciphers" touches on everything from the smoke signals used by the Native Americans to the encryption devices used by government agencies and the military. As well as covering the history of the development of codes and ciphers, this book will also have practical information and advice on how to make codes (whether by pencil and paper, or by computer) and, more importantly, how to break codes! The topics covered are: Native American smoke signals, Masonic signals, flags, and semaphore; Morse code, Braille, ASCII computer language; Letter substitution, both mono-alphabetic and poly-alphabetic; Computer algorithms; The role of codes and ciphers throughout history, for example the American Civil War, the First and Second World Wars; The development of code-breaking devices such as the Enigma machine, which was developed by the Allies during the Second World War to decipher German communications.

Genres: Nonfiction

191 pages, Paperback

First published February 1, 2006

Reviews

[Rose]

Readable introduction to codes and ciphers, but probably not the best one around, and certainly not a book I'd recommend if you want "practical information on how to make codes and...how to break them".

It has a pretty pointless section on "Leet" and "Txt talk", apparently "new global codes" with "great social kudos for the young".

Leet, it is claimed, "enables rapid communication to take place by using keyboard characters as shortcuts". Some examples of this much more rapid way of typing are "13375P34K" and representing A as /-\ or B as |: - I rather think the author has missed the point of l33t. The book gives a few handy translations of l33t-speak, including this invaluable entry:

yo = 'yo', an alternative to 'Hi'.

The section on txt talk helpfully points out, without once using the words "smilies" or "emoticons":

Keyboard or handset characters are also used to create pictorial messages such as these ones (try tilting your head if you don't see how it works):
0:-) = angel :-! = bored %-) = confused

So far you might be thinking that this isn't quite what you expected from a book about codes and ciphers. But don't worry, there's also a section on sign language, which manages in 5 sentences to make 2 major errors. It claims that the two most common sign languages are American Sign Language and Signed English. Signed English is not a language; it's just a mode of English, like writing; genuine sign languages have their own grammar, syntax etc. I haven't been able to find out which sign language actually is the second most common, as census data doesn't seem to exist for many sign languages, but it might be Chinese Sign Language, given that there are 20 million deaf people in China (Ethnologue).

Moving on, it states that "Unlike Signed English (which has gestures for words), American Sign Language uses an alphabet, allowing messages to be spelt out." Um...what? Both Signed English and ASL use fingerspelling and signs representing concepts, objects, etc (which aren't gestures). If ASL only used fingerspelling, it would just be a very slow manually-coded mode of English.

Anyway, let's leave these and move into the main part of the book: secret and hidden codes. This section is generally much better, but I have a couple of quibbles, such as the contradictions within the text.

For example, the "police code alphabet" (Alpha, Bravo, Charlie etc) is listed as a secret code - one to be used "when there is danger of other ears listening in" - even though it also explains that it is used for "accuracy in spelling out important words and phrases".

In addition, the book states that "A digraph is two letters that together make one sound.", giving examples such as "on", "nd" and "to". Single sounds? I think not. In cryptography, a digraph is any pair of adjacent letters, even though in orthographics it does refer to two letters making one sound (as we now teach 4-year-olds in the UK).

There are also some unnecessary repetitions of parts such as lists of common letters in different positions within words. That Alice, Bob, and Eve are used to represent the two parties exchanging coded information and the interceptor, respectively, is also repeated - I think I counted three times.

The timeline of coding developments stops in 1991, even though the book was published in 2006, and one might think that some interesting things might have happened in cryptography in the meantime - especially connected to the rising use of the Internet, online payments and banking, hacking etc.

In summary, the book is alright, but you don't get the impression that the author is an expert on cryptography. It's accessible to laypeople, but it's not always accurate in matters I do know about, so it probably has mistakes in the parts about cryptography I don't know so much about. I am sure that there are better and equally accessible introductions to cryptography around.

[Keeko · Rating 5 out of 5]

Darn fine book. He did a great job of describing a lot of complex information clearly, and I liked how he weaved in the history of the codes.

[Kevinhoytjr · Rating 5 out of 5]

Excellent truly revealing.