Cryptanalysis

A good book that reviews methods for pen-and-paper solution of simple substitution and transposition ciphers. Dating from before World War II, the main interest here is historical. Nevertheless, it is quite well written and enjoyable, with many examples to solve (most solutions included, but there are a few unsolved ciphertexts).

This Dover reprint is an excellent treatment of classic cryptographic and cryptanalytic techniques. Cyphering techniques from Caesar to World War I, including both transposition and substitution ciphers, are well covered, as are the classical cryptanalysis techniques for breaking them. You will not find any discussion of comtemporary digital ciphering or computer-based cryptanalysis, but the work, although dated, is an excellent introduction to the fundamentals of both cipher making and breaking.

This appears to be a reprint of the little book by the same title that utterly consumed me, probably for hundreds of hours, in the 1970's. It was old then, and looks even older now. And yet, pushing letters around on a page is timeless. It's laughably low-tech and yet, utterly modern, all at the same time. Some of the tricks and techniques described are so profound and clever, they are reminiscent of calculus in how they demonstrate the power of the well-applied human mind. This book can be an absorbing hobby all by itself. Plus when I found a coded note written by some girls in my junior high school, I was able to read it...

As a former codebreaker with the ASA/NSA during the VN war, I often found it helpful to have a copy of Helen's book handy, and spent many enjoyable hours solving the sample ciphers provided. This valuable book not only describes many historically significant encipherment methods, but also goes into detail about how to break them. Afficianados of manual ciphers might also wish to contact others with similar interests and can do so through the American Cryptogram Association at www.cryptogram.org.

I bought this book over 40 years ago... It is, by far, the best book for pen-and-pencil cryptogram solving that I have found. It gives sufficient information to allow attacking any pen-and-pencil cryptogram. If it is followed by Bauer's "Decrypted Secrets," one would have a very thorough introduction to methods of solutions (Bauer is quite mathematical, but also recommended to the mathematically inclined). An excellent introduction with a great deal of useful information that is probably the best available source for pre-computer techniques.