The Cracking Code Book

Оглавление

Simon Singh. The Cracking Code Book

SIMON SINGH. the. cracking codebook. How to. make it, break it, hack it, crack it

Contents

Introduction

1 The Cipher of Mary Queen of Scots

THE EVOLUTION OF SECRET WRITING

THE ARAB CRYPTANALYSTS

CRYPTANALYZING A CIPHERTEXT

RENAISSANCE IN THE WEST

THE BABINGTON PLOT

2 The Anonymous Codebreaker

MR BABBAGE VERSUS THE VIGENÈRE CIPHER

FROM AGONY COLUMNS TO BURIED TREASURE

3 The Mechanization of Secrecy

THE DEVELOPMENT OF CIPHER MACHINES

CRACKING THE ENIGMA

THE GEESE THAT NEVER CACKLED

4 The Language Barrier

DECIPHERING LOST LANGUAGES AND ANCIENT SCRIPTS

5 Alice and Bob Go Public

GOD REWARDS FOOLS

PRIME SUSPECTS

THE SECRET HISTORY OF PUBLIC-KEY CRYPTOGRAPHY

6 Pretty Good Privacy

THE FUTURE OF CRYPTOGRAPHY

The Codebreaker’s Challenge

Appendix A

Appendix B

Appendix C

Appendix D

Appendix E

Acknowledgements

Further Reading

Index

About The Author

Also By Simon Singh

Copyright

About the Publisher

Отрывок из книги

To the Teachers and Mortals

who took the time to inspire me

.....

Now we must ask ourselves which vowels are represented by O and X. They are probably e and a, the two most popular vowels in the English language, but does O = e and X = a, or does O = a and X = e? An interesting feature in the ciphertext is that the combination OO appears twice, whereas XX does not appear at all. Since the letters ee appear far more often than aa in plaintext English, it is likely that O = e and X = a.

At this point, we have confidently identified two of the letters in the ciphertext. Our conclusion that X = a is supported by the fact that X appears on its own in the ciphertext, and a is one of only two English words that consist of a single letter. The only other letter that appears on its own in the ciphertext is Y, and it seems highly likely that this represents the only other one-letter English word, which is i. Focusing on words with only one letter is a standard cryptanalytic trick, and I have included it among a list of cryptanalytic tips in Appendix B. This particular trick works only because this ciphertext still has spaces between the words. Often, a cryptographer will remove all the spaces to make it harder for an enemy interceptor to unscramble the message.

.....