Skip to main content
main-content

Über dieses Buch

This accessible textbook presents a fascinating review of cryptography and cryptanalysis across history. The text relates the earliest use of the monoalphabetic cipher in the ancient world, the development of the “unbreakable” Vigenère cipher, and an account of how cryptology entered the arsenal of military intelligence during the American Revolutionary War. Moving on to the American Civil War, the book explains how the Union solved the Vigenère ciphers used by the Confederates, before investigating the development of cipher machines throughout World War I and II. This is then followed by an exploration of cryptology in the computer age, from public-key cryptography and web security, to criminal cyber-attacks and cyber-warfare. Looking to the future, the role of cryptography in the Internet of Things is also discussed, along with the potential impact of quantum computing.

Topics and features: presents a history of cryptology from ancient Rome to the present day, with a focus on cryptology in the 20th and 21st centuries; reviews the different types of cryptographic algorithms used to create secret messages, and the various methods for breaking such secret messages; provides engaging examples throughout the book illustrating the use of cryptographic algorithms in different historical periods; describes the notable contributions to cryptology of Herbert Yardley, William and Elizebeth Smith Friedman, Lester Hill, Agnes Meyer Driscoll, and Claude Shannon; concludes with a review of tantalizing unsolved mysteries in cryptology, such as the Voynich Manuscript, the Beale Ciphers, and the Kryptos sculpture.

This engaging work is ideal as both a primary text for courses on the history of cryptology, and as a supplementary text for advanced undergraduate courses on computer security. No prior background in mathematics is assumed, beyond what would be encountered in an introductory course on discrete mathematics.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction – A Revolutionary Cipher

Abstract
Cryptology is the science of secret writing. It is made up of two halves; cryptography consists of the techniques for creating systems of secret writing and cryptanalysis encompasses the techniques of breaking them. Over the past 2500 years, cryptology has developed numerous types of systems to hide messages and subsequently a rich vocabulary in which to describe them. In this chapter we introduce the reader to the vocabulary of cryptology, explain the differences between codes and ciphers and begin the discussion of how to decipher an unknown message.
John F. Dooley

Chapter 2. Cryptology Before 1500 – A Bit of Magic

Abstract
Cryptology was well established in ancient times, with both Greeks and Romans practicing different forms of cryptography. With the fall of the Roman Empire, cryptology was largely lost in the West until the Renaissance, but it flourished in the Arabic world. The Arabs invented the first reliable tool for cryptanalysis, frequency analysis. With the end of the Middle Ages and the increase in commerce and diplomacy, cryptology enjoyed a Renaissance of it’s own in the West. This chapter examines the most common cipher of the period, the monoalphabetic substitution cipher and then looks at the technique of frequency analysis that is used to break the monoalphabetic substitution. An extended example is given to illustrate the use of frequency analysis to break a monoalphabetic.
John F. Dooley

Chapter 3. The Black Chambers: 1500–1776

Abstract
The period from 1500 through the middle of the eighteenth century saw the creation of modern nations and city-states. It also saw increased use of codes and ciphers in diplomacy, the military, and commerce. The nomenclator, a marriage of the code and cipher is a product of this period. This period also saw the creation of a cipher that would remain “unbreakable” for 350 years, the polyalphabetic substitution cipher. This chapter traces the history of the Black Chambers, those organizations created by the newly formed nations to break the codes and ciphers of their neighbors, and it describes the nomenclator and the evolution of the polyalphabetic substitution cipher known as the Vigenère cipher.
John F. Dooley

Chapter 4. Crypto Goes to War: The American Revolution

Abstract
The birth of a new nation necessitated the creation of secret writing by the representatives and military officers of that nation. At the beginning of the American Revolution the use of codes and ciphers and secret inks to hide the contents of diplomatic and military intelligence messages was completely absent from American communications. It was up to the amateurs who ended up leading the Continental Army and the Congress to create and use systems that would protect their correspondence from British eyes. The British were not much more sophisticated in their secrecy systems than the Americans in cryptography and steganography. Regardless, when both sides are learning as they go there are successes and failures.
John F. Dooley

Chapter 5. Crypto Goes to War: The American Civil War 1861–1865

Abstract
The nineteenth century marked the beginning of the use of technology in many areas, and cryptology was no exception. The invention of the telegraph and its rapid and easy communication ushered in the twilight of traditional forms of cryptography. It also marked the beginning of a century and a half of rapid development of new techniques in both cryptography and cryptanalysis, all starting during the American Civil War. This chapter looks at the cipher systems used by both the Union and Confederate sides during the American Civil War. It also presents a description of the biggest cryptanalytic breakthrough of the nineteenth century, the breaking of the unbreakable cipher, the Vigenère.
John F. Dooley

Chapter 6. Crypto and the War to End All Wars: 1914–1919

Abstract
The use of wireless telegraphy – radio – during World War I marked the advent of modern cryptology. For the first time, commanders were sending enciphered messages to front line troops and for the first time, the enemy had an enormous amount of ciphertext to work with. This spurred the development of more complicated codes and ciphers and eventually led to the development of machine cryptography. World War I is the first time that the Americans had a formal cryptanalytic organization. It is the beginning, in all the nations involved in the conflict, of the bureaucracy of secrecy. In the United States it marks the first appearance of the two founding fathers of modern American cryptology, Herbert O. Yardley and William F. Friedman. This chapter introduces Herbert Yardley and William Friedman and examines some of the cryptographic systems used during World War I.
John F. Dooley

Chapter 7. The Interwar Period: 1919–1941

Abstract
In the period between the two World Wars Americans struggled with the morality and the cost of reading other people’s mail. Herbert Yardley created his American Black Chamber and established for the first time that the United States should be in the position to protect itself and further it’s own interests with the use of permanent professional cryptographers and cryptanalysts. William Friedman, working in the Army, established the organization that would be the Army cryptologic backbone during the Second World War. Friedman and the team he put together during the 1930s would move American cryptology into the machine age in both cryptography and cryptanalysis. Despite Yardley’s flaws and failure American would never again be without a cryptanalytic bureau. This chapter briefly examines the professional lives of Herbert Yardley and William Friedman and discusses their contributions to the growth of the American cryptologic infrastructure.
John F. Dooley

Chapter 8. The Rise of the Machines: 1918–1941

Abstract
The volume of cipher traffic that was made possible by radio showed the need for vastly increased security, speed and accuracy in both enciphering and deciphering messages. The use of mechanical and electromechanical machines to do the encipherment was a logical outgrowth of this need. The first electromechanical rotor cipher machines began to appear right after World War I and the next three decades saw their steady improvement in both complexity and speed. The Enigma, the Typex and the M-134C/SIGABA were the epitome of these machines and the efforts to create and cryptanalyze them led us into the computer age. This chapter examines the history of cipher machines in the first part of the twentieth century and looks in some detail at the cryptographic construction of the Enigma and the Japanese Purple machine.
John F. Dooley

Chapter 9. Battle Against the Machines: World War II 1939–1945

Abstract
While the 1930s saw the first efforts to cryptanalyze the new cipher machines, the advent of World War II made this work must more imperative. The Enigma, the Typex and the M-134C/SIGABA were the epitome of these machines and the efforts to create and cryptanalyze them led us into the computer age. This chapter examines the race to break the ever more sophisticated cipher machines of the 1940s and looks in some detail at the cryptographic construction of the Enigma and the M-134C/SIGABA.
John F. Dooley

Chapter 10. The Machines Take Over: Computer Cryptography

Abstract
Modern cryptology rests on the shoulders of three men of rare talents. William Friedman, Lester Hill and Claude Shannon moved cryptology from an esoteric, mystical, strictly linguistic realm into the world of mathematics and statistics. Once Friedman, Hill, and Shannon placed cryptology on firm mathematical ground, other mathematicians and computer scientists developed the new algorithms to do digital encryption in the computer age. Despite some controversial flaws, the U.S. Federal Data Encryption Standard (DES) was the most widely used computer encryption algorithm in the twentieth century. In 2001 a much stronger algorithm, the Advanced Encryption Standard (AES) that was vetted by a new burgeoning public cryptologic community, replaced it. This chapter introduces Hill and Shannon and explores the details of the DES and the AES.
John F. Dooley

Chapter 11. Alice and Bob and Whit and Martin: Public-Key Cryptography

Abstract
The key exchange problem occurs with symmetric cipher systems because the same key is used for both enciphering and deciphering messages. This means that both the sender and receiver must have the same key and it must be distributed to them via a secure method. While this is merely inconvenient if there are only two correspondents, if there are tens or hundreds of people exchanging secret messages, then distributing keys is a major issue. Public-key cryptography eliminates this problem by mathematically breaking the key into two parts, a public key and a private key. The public key is published and available to anyone who wants to send a message and the private key is the only key that can successfully decipher a message enciphered with a particular public key. This chapter investigates the mechanisms used to implement public-key cryptography.
John F. Dooley

Chapter 12. Web and Mobile Device Cryptology

Abstract
In 1993 the first graphical web browser, Mosaic, was written. Since then personal security and privacy has been under attack. New algorithms and types of browser and device security have been developed and continue to be spread as more and more attacks occur.
John F. Dooley

Chapter 13. Cyber Weapons and Cyber Warfare

Abstract
A cyber attack is any type of offensive action employed by nation-states, individuals, groups, or organizations that targets computer information systems, infrastructures, computer networks, or personal computer devices by various means of malicious acts. Cyber attacks typically originate from an anonymous source that steals, alters, or destroys a specified target by hacking into a vulnerable system (https://​en.​wikipedia.​org/​wiki/​Cyberattack). Cyber warfare involves the actions by a nation-state to attack and attempt to damage another nation’s computers or information infrastructure through, for example, computer viruses, worms, or denial-of-service attacks. In this chapter we’ll look at various types of cryptologic techniques used in cyber attacks and discuss the possibilities of using cryptology in cyber warfare; the chapter does not go deeply into system vulnerabilities and attacks or into cyber attack prevention, mitigation, or response.
John F. Dooley

Chapter 14. Cryptology and the Internet of Things

Abstract
The ubiquity of mobile devices and the increasing penetration of “smart” home devices and autonomous vehicles are the first signs of the Internet of Things. When all of your personal devices, your appliances, your car, and your home become “smart” and connected there are a number of issues that will need to be addressed including privacy, transparency, open access, and publicity. Who collects your data, where it is stored, and how it is stored and transmitted will all be important topics going forward. Cryptology will be central to all of these questions.
John F. Dooley

Chapter 15. What Is Next in Cryptology?

Abstract
What would happen if all of the algorithms in public-key cryptography suddenly could be broken in seconds or minutes? Those algorithms, like RSA and elliptic curve cryptography are the ones that we depend on for Internet commerce. What if they were all of a sudden useless? Would society collapse? Would commerce be at an end? That is the promise and the danger of quantum computers.
John F. Dooley

Chapter 16. Cipher Mysteries

Abstract
Over the last 2500 years or so there have been any number of cipher messages that have gone lost, or which have had their keys lost, or for which the entire system used to encipher them has been forgotten. Sometimes this happens deliberately, and sometimes by accident. Sometimes the messages are fairly innocuous, and sometimes their solution could lead to vast treasures or change the course of nations. For some of these unsolved messages, cryptanalysts over the years have spent decades or even careers looking in vain for a solution. Some of these messages have been judged to be hoaxes, for others we’re not so sure. In this chapter we’ll take a look at four famous cipher messages for which we have no solution – yet.
John F. Dooley

Backmatter

Weitere Informationen

Premium Partner

    Bildnachweise