文件名称：Codes and Ciphers: Julius Caesar, the Enigma, and the Internet
文件大小：1.22MB
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更新时间：2011-09-11 02:51:21
密码学
Codes and Ciphers: Julius Caesar, the Enigma, and the Internet
代码和加密
by R. F. Churchhouse
Publisher: Cambridge University Press (December 6, 2001)
内容介绍：
本书描述和分析了许多加密系统，从最早期到最现代的、复杂的系统以及互联网环境下的加密等等
The ability to convert data into a form that is readable only by a selected group has been a matter of utmost importance for thousands of years. The fate of entire nations has rested on the ability of a nation to keep their messages secure or accurately unravel the messages of opponents. The most celebrated cases involve instances of war, where the messages sent by the Germans and Japanese were intercepted and decrypted by the allies. While not decisive in the outcome of the war, the knowledge gained was of enormous value and did a great deal to assist in the victory. By far, the most well known case is that of the Enigma machine used by the Germans in world war two. The British were able to break the code and the knowledge they obtained made a significant difference in the early years of the war.
Encryption is now a foundation pillar of modern society. Trillions of dollars are now electronically exchanged over the course of a year, and the entire world economy is now dependent on the ability of computers to exchange data in a manner that is accurate and secure from fraud. While security over the Internet is the most widely cited example, most of the data is exchanged over private lines.
The first documented case of encryption being used in war is when Julius Caesar used a simple substitution cipher to send orders to his troops. That and all similar codes is where the book begins. After that, there is a very detailed examination of the Enigma and Hagelin machines, right down to how the wheels interact. This part of the book was by far the most interesting, as well as the descriptions of how it was possible for the allied cryptographers to break the Enigma code. It turns out that the breaking of the codes was not due to a flaw in the machine, but in the way it was used. The remaining part of the book is filled with a description of public key cryptography and the applications for the Internet.
The sections on the substitution ciphers and public key cryptography are good but fairly standard. Problems are given at the end of each chapter and solutions are in the back of the book. What makes this book unique is the mechanical descriptions of the Enigma and Hagelin cipher machines. If you are interested only in the mathematics of encryption, then you will most likely not find them interesting. However, if you are like me and are interested in the mechanical aspects of the machines, then you will like it.
http://www.amazon.com/exec/obidos/tg/detail/-/052181054X/qid=1124437337/sr=1-1/ref=sr_1_1/102-6019928-1193731?v=glance&s=books