43 pages • 1 hour read
Simon SinghThe Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography
Nonfiction | Book | Adult | Published in 1999A modern alternative to SparkNotes and CliffsNotes, SuperSummary offers high-quality Study Guides with detailed chapter summaries and analysis of major themes, characters, and more.
Chapters 3-4Chapter Summaries & Analyses
Chapter 3 Summary: The Mechanization of Society
After the invention of the telegraph, the next major technological development in the science of telecommunications was the radio, invented by Guglielmo Marconi in the closing years of the 19th century. The invention of the radio was a marvelous discovery, but the military viewed its existence as both ripe for exploitation and, at the same time, rife with probable security threats: “[T]he all-pervasive property of radio is also its greatest military weakness, because messages will inevitably reach the enemy as well as the intended recipient” (146). The use of radio for military purposes was first widely deployed during the First World War, and the first method of radio encryption was the use of a German cipher typically known as the ADFGVX cipher.
During the war, the warring nations commissioned coalitions of military cryptologists and analysts. The French coalition was widely regarded as the most skilled group in Europe, developing a method of identifying telegraph operators by the way they transmitted messages. Additionally, radio analysis also led to the use of what is known as traffic analysis, whereby the source of a message (and possibly its destination) could be discovered even while the encrypted message remained a mystery.
During the war, different attempts at radio encryption were tried, but there were numerous instances of wartime radio transmission interceptions leading to great moments of military genius and success thanks to the increased amount of information available for opposing forces. Intercepted telegrams and radio transmissions were crucial in the decisive victories and decisions that would lead to the conclusion of the war. A new method of implementing the Vignere cipher was discovered that allowed for its implementation to be secure from frequency analysis investigation.
Random cipher keys were also experimented with, wherein both sender and recipient had codebooks containing randomly sequenced letters and numbers that would completely remove any possibility of analysis since there was no intrinsic order to the cipher. “The onetime pad cipher overcomes all previous weaknesses” (169) thanks to this randomness, but its implementation was rife with obstacles—not the least of which was the necessity of perpetually creating new random key sequences. In the end, while such a method of encryption was literally unbreakable, it was far too onerous a system to implement on a wide scale: “A onetime pad is practicable only for people who need ultrasecure communication, and who can afford to meet the enormous costs of manufacturing and securely distributing the keys” (173).
Finally, in the search for ever-greater methods of encryption, the Enigma machine was invented. While the use of a machine of some kind for this purpose was not new—in fact, the “earliest cryptographic machine [was] the cipher disk” and was “invented in the fifteenth century” (174)—Arthur Scherbius, a German inventor, devised Enigma, “the most fearsome system of encryption in history” (178). It was constructed of a keyboard for entering the plaintext, a system of scrambling disks in which the plaintext message was transformed and modified, and a display of lights that lit up in order to indicate the corresponding cipher characters. The Enigma machine was a technical success but did not find acceptance quickly. Initially, Scherbius planned to market the device toward both military and commercial ends, but businesses were not interested due to the high cost (over $30,000 in today’s money).
The military applications were obvious, however, and it quickly became the premier method of German military encryption:
Over the next two decades, the German military would buy over 30,000 Enigma machines…[which] provided the German military with the most secure system of cryptography in the world, and at the outbreak of the Second World War their communications were protected by an unparalleled level of encryption (198).
Chapter 4 Summary: Cracking the Enigma
After the conclusion of the First World War, the Allied nations grew lax in their relations with Germany; they assumed that Germany’s defeat signaled the end to any possibility of German offense in the years to come. The nation that could not afford to relax, however, was Poland. As a means of defense, Poland established the Biuro Szyfrów, their own version of a secret government cryptology force, and set about attempting to break the Enigma cipher.
The first to contribute toward the deciphering of Enigma was Hans-Thilo Schmidt, a veteran of the First World War and a German. Disaffected by the aftermath of the war, Schimdt began to sell state secrets related to Enigma to the highest bidder, providing Allied forces with the means of replicating the machine. The problem, however, was that even with a working machine, the code could not be cracked without an intimate knowledge of the settings used in each code transmission.
The Polish forces broke with the longstanding assumption that linguists would be the best choice for code breakers and began recruiting highly capable mathematicians for the job: “Enigma was a mechanical cipher, and the Biuro Szyfrów reasoned that a more scientific mind might stand a better chance of breaking it” (206).
Eventually, the majority of the work was done by the mathematician Marian Rejewski. Focusing on Enigma’s use of consistent, if not rare, repetitions, Rejewskiw was able to begin unscrambling Enigma’s cipher: “It took an entire year to complete the catalogue, but once the Biuro had accumulated the data, Rejewski could finally begin to unravel the Enigma cipher” (213). Unbeknownst to Rejewski and the team, however, was that Polish command had stolen the keys to Enigma and were already aware of how to decode the messages thanks to their spies. They refused to tell the cryptologist team, hoping to push the team to actually find a solution to the Enigma code.
Practically from the start, British and French cryptologists had given up hope of ever cracking Enigma’s cipher, but the Polish teams demonstrated that it could be possible. The Polish strategy of employing mathematicians in the hunt inspired the British to set up a separate headquarters at Bletchley Park (apart from their already established team at Room 40 in London), which would serve as the location for the newly founded Government Code and Cypher School.
The first major breakthrough occurred when the Bletchley team were able to identify what they called “cillies,” “obvious message keys” (225) that Enigma operators behind enemy lines would choose out of carelessness or a need for haste. As such, the first hints were discovered not in the cipher itself, but in the human beings in charge of the cipher: “Cillies were not weaknesses of the Enigma machine, rather they were weaknesses in the way the machine was being used” (226).
The eventual breaking of the Engima code was thanks to the work of Alan Turing, a Cambridge mathematician. Turing imagined the creation of the code-breaking machines, dubbed “bombes,” which slowly chipped away at the code in use by Enigma and its operators. Meanwhile, plans were constantly put into action to steal codebooks. Some plans were successful: one, dubbed “Operation Ruthless,” allowed U-Boats to be located and targeted but boarded and stripped of their contents before sinking.
Eventually, Turing and the teams at Bletchley were able to crack the Enigma ciphers and were able to decipher messages of Axis forces. While not the only reason for the rapid end to the war, it is certain that the operations at Bletchley were an essential factor in winning the war for the Allied forces: “What is certain is that the Bletchley codebreakers significantly shortened the war” (254).
Chapters 3-4 Analysis
The next grouping of chapters moves from some of the historical considerations of codes and ciphers—basic information, as well as historical developments in the medieval and early modern periods—and takes the narrative into the modern era with the invention of the telegraph and the early 20th century.
Before the invention of the telegraph, the need for secrecy in private communication was certainly a concern, but it was a concern in relation to someone absconding with a physical message: a letter, a note, a physical object of some kind. With the telegraph, however, the message could potentially be viewed by any number of people: Since it is not a physical object while being sent, any number of people might intercept the message as it is in the airways being sent.
The radio raised similar concerns. In the past, the possibility of sabotage was generally limited to only the few people involved in a clandestine act of communication and the message they were sharing, either by word of mouth or by some kind of written message. Now, however, anyone with an extra radio tower was able to access the messages of everyone using the system. The military was the first to realize the massive potential of such a system and at the same time the enormous security risk such technology posed. With the introduction of more people to the chain of communication—the telegraph operators and the host of people who could easily pick up a message on the wire—the approach to cryptology and cryptoanalysis needed to adapt to the changing times. The tension between privacy and ease of communication that is ever present in the 21st century began here.
While the inventors of new cryptographic machinery initially imagined their inventions being applicable to both military and business applications, the private sector was slow to pick up on the use of such technology due to the prohibitive cost. The military, on the other hand, had no such qualms. One of the earliest to adopt the new cryptanalytic technology was the Polish secret service, as the author emphasizes in the fourth chapter. One of the most significant innovations that Poland made was the shift from filling the staff with linguists to employing mathematicians instead.
Historically, the areas of secret messages and the manipulation of language was naturally the domain of experts in languages. With the shift to a highly mechanized mode of encryption that involved complex machinery and voluminous amounts of mathematics, Poland determined that it needed to take a new direction with its attempts at breaking codes and ciphers. Deciphering codes had always involved some manner of mathematical and statistical analysis, but the Enigma machine and other encryption machines like it were making use of unprecedented mathematical processes to transform their codes. It was a necessary evolution of the process to bring in mathematicians and other technically inclined geniuses to create an intellectually diverse group creative enough to break the hardest codes yet created.
Interestingly enough, the increased reliance on mathematical processes shifted some of the analysis away from the actual codes to the circumstances surrounding the intercepted messages. Now a cryptoanalysis team would investigate much more than the cipher, determining if there was anything to discover in the timing of messages, their locations, and any other aspect of the communication process that could be affected by human agency and error. The more information that could be gleaned from the human aspect, the greater chance deciphering teams would have of ruling out certain possibilities for the messages they worked on.
