Excerpts from "The Codebreakers"
Author: David Kahn
The book describes in detail the history of cryptology. The author begins with the emergence of writing and traces the development of this science up to the middle of the last century. The book was written in 1967.
A bit of terminology: Cryptology is the science dealing with methods of encryption and decryption. Cryptanalysis is the science of methods for decrypting encrypted information without the intended key, as well as the process of such decryption. Cryptography is the science of methods for ensuring confidentiality, integrity, authentication, and encryption.
History
Almost 4000 years ago, in the ancient Egyptian city of Menet-Khufu, an experienced scribe drew hieroglyphs telling the story of his master's life. In doing so, he became the founder of the documented history of cryptography. His text was not secret writing, but merely consisted of unusual hieroglyphic symbols instead of more familiar ones. The unknown scribe was not trying to make the text difficult to read, but to give it importance.
The Arabs were the first to discover and describe methods of cryptanalysis. This people created one of the most developed civilizations that history has ever known. Arab science flourished. Medicine and mathematics among the Arabs became the best in the world. The composition of word puzzles, rebuses, and puns became widespread. Grammar became the main academic subject and included secret writing.
The Arabs' interest in cryptography appeared early. In 855 AD, an Arab scholar named Abu Bakr Ahmed ben-Ali ben-Wahshiya an-Nabati included several classical cipher alphabets in his "Book of the Great Desire of Man to Unravel the Mysteries of Ancient Writing."
In the Middle Ages, cryptography began to be used for political correspondence. And it was a science exclusively of enthusiasts. They were hired by royal courts, made close associates, and well paid for deciphering enemy letters and creating strong ciphers. Later, states, realizing the importance of this discipline, organized "Black Chambers". These were bodies engaged in the interception and decryption of correspondence, located in post offices. The first such organization appeared in France in the 17th century, and a system of truly mass correspondence interception was organized in France during the reign of Louis XV. Another mention in history confirms the important role of cryptography in political life:
- In the 17th century, John Trevanion, expecting imminent execution at the hands of Cromwell's supporters, received a letter that was carefully examined by his jailers before being handed to him. Reading every third letter after each punctuation mark in this letter, he learned that "in the east wall of the chapel, one panel opens." During evening service, Trevanion escaped.
Cryptology in the Soviet Union
Although the appearance of secret writing in Russia dates back to the 12th-13th centuries, the use of cryptography for securing state correspondence began only in the era of Peter the Great.
During World War II, agents of the Soviet secret police and GRU actively sought valuable information in many parts of the world. Three spy groups ensured an almost continuous flow of intelligence data to Moscow. The legendary "Lucy" spy ring in Switzerland, the "Red Orchestra" in Germany, and the Sorge group in Japan provided the Kremlin with an endless stream of detailed and reliable intelligence information.
How seriously the USSR treated security issues is illustrated by the following case. On the eve of the new year 1956, Soviet diplomats preferred to let their embassy in Ottawa burn to the ground rather than allow Canadian firefighters onto its territory, lest they accidentally see the embassy's ciphers and codes.
Documents to be sent to Moscow from embassies were photographed onto film and sent via diplomatic pouch in undeveloped form, so they would be exposed if the mail was opened by an unauthorized person. This procedure was also applied to all materials arriving at the embassy. When photographic film arrived from Moscow, it was developed, one enlarged print was made from each frame, and then the negative was destroyed. In turn, after Moscow confirmed receipt of the photographic film from the embassy, all originals there were immediately destroyed. In the late 1950s, lockable containers began to be used for transporting undeveloped film. If an attempt was made to open such a container, acid was automatically injected onto the film stored inside.
Reports from Soviet intelligence officers were sometimes written in Russian in plain text using spy jargon: the word "packaging" meant encryption, "open packaging" meant plaintext, "bank" meant dead drop, etc. In addition, such letters widely used code names. For example, in Canada, Soviet military attache Colonel Zabotin had the code name Grant, and Allan May was Alex. How effective this precaution was can be seen from the report of the Canadian commission on the activities of the Soviet intelligence group. It stated that the commission members were unable to identify the agents operating under the pseudonyms Galya, Gini, Goliya, Grin, and Sarensen, although it was definitively established that they were Zabotin's agents.
Cryptology in Nazi Germany
Significant assistance to German cryptanalysts from Department "Z" (the body of military intelligence and counterintelligence of the German Empire) was provided by an information group headed by Pastor Ziegenrücker. This group collected data from radio broadcasts, foreign ministry memoranda, and foreign newspapers. Department "Z" had language specialists for every country large enough to maintain a diplomatic corps abroad. The breaking of ciphers from a total of 34 countries around the world, including England, the United States, and France, testified that the cryptanalysts of Department "Z" were not working in vain.
The head of the Japanese spy network in Europe sold the Germans the active codes of the Yugoslav General Staff, as well as those of the diplomatic services of Brazil, the Vatican, Portugal, and Turkey. The Germans were incredibly pleased with such an acquisition.
The military sector of the German embassy included hundreds of employees, forming one of the largest German spy units abroad. They were housed in the embassy building and actively engaged in decrypting intercepted messages, taking advantage of Spain's exceptionally favorable geographical position for interception from its territory.
A company under the command of Captain Seebohm obtained strategic information for Rommel. It recorded all conversations, used direction-finding to determine the concentration of enemy troops and tanks, learned the disposition and designations of units, and studied English cipher telegrams for the purpose of decryption.
German agents split a sheet of paper in half, wrote text with invisible ink on the inner surface, and then rejoined the halves. Since the ink was inside the sheet, no reagent applied to its outer surface could develop it.
The Germans employed a method of secret writing that FBI Director Hoover called "a masterpiece of German intelligence." This was the so-called microdot — a tiny photograph that reproduced the text of a letter with sufficient clarity.
A German intelligence group operated in Mexico, making microphotographs of American trade and technical publications that were banned from export and sending them in large batches to secret addresses in Europe, sometimes with up to 20 microdots in a single letter. Stolen technical drawings and schematics were also sent across the ocean this way.
Cryptology in the United States
Censorship
America, in protecting its own interests, has historically not hesitated to violate human rights.
After the Japanese attack, the United States created its own censorship body. Soon its staff numbered about 15,000 employees, located in 90 buildings across the country, checking about a million letters daily, wiretapping countless phone calls, screening films, newspapers, magazines, and reviewing radio scripts. Millions of Americans received letters in envelopes with traces of the censor's scissors and a stamp reading "Opened by Censorship."
To block as many steganographic communication channels as possible, American censorship categorically prohibited sending a number of message types by mail. Correspondence chess matches were canceled. Crossword puzzles were cut out of letters because censors didn't have time to solve them to check if they contained secret messages. Newspaper clippings were removed from mail as they might contain secret text. Report cards were not allowed to be sent by mail. One letter with knitting instructions was held until the censor knitted a sweater from them to check if they contained any hidden information.
Censors removed suspicious stamps and replaced them with others of the same value but with a different number and design. Blank paper, which US residents often sent to their relatives living in countries where paper was scarce, was also replaced from corresponding stocks to prevent the use of invisible ink. Even children's drawings that parents sent to grandparents were confiscated, as these drawings might contain encoded maps or diagrams.
According to rules established by American censorship for the telegraph, it was forbidden to send any text that was incomprehensible to the censor. Sometimes censors deliberately paraphrased messages. This practice gave rise to a classic anecdote from World War I. A telegram reading "Father died" landed on the censor's desk. The censor thought for a moment, crossed out "died," wrote "passed away," and sent the telegram on. Soon after, a reply telegram arrived asking: "Did Father die or pass away?"
No American company could use its own telegraph code without censorship permission.
Telegrams ordering flowers ("Deliver to my wife three white orchids Saturday") offered such a convenient opportunity for transmitting secret information that censors banned specifying flower names and delivery days.
Precautionary measures were also taken regarding the media. Newspapers had to exercise caution when publishing various advertisements. Commercial radio stations were brought under control, as they could quickly and easily transmit coded signals to enemy submarines or agents, as was vividly demonstrated by a military intelligence officer a year before Pearl Harbor. He managed to transmit a secret message using coded language. Neither the announcer who read the coded text, nor the radio station director, nor the thousands of radio listeners had any idea what message they had heard on the radio.
The censorship service canceled telephone and telegraph requests for playing particular musical pieces on the radio, and ordered that requests sent by mail be delayed indefinitely. These measures were intended to eliminate the possibility of transmitting messages to enemy submarines using a popular song. Similar measures were taken regarding the broadcasting of personal announcements by radio stations.
Suspicious financial reports sent by telegram were given for review to an employee familiar with accounting. And an employee who was an amateur gardener could accurately determine how truthful a letter about setting up tulip beds was.
Letters in unknown languages were sent to a linguistic department that had translators for rare languages.
Here is one well-known case of cracking a jargon code from World War I. An English censor became suspicious of the excessively large daily telegraph orders for cigars (mainly from English port cities) placed by "two Dutch businessmen." One day from Portsmouth they ordered 10,000 "Corona" cigars. The next day from Plymouth they demanded a large batch of cheaper cigars. Then, within a single night, all residents of Newcastle turned into inveterate smokers. It seemed that the entire population of England's coastal areas had suddenly felt an irresistible craving for smoking — so monstrously had the demand for cigars grown.
Once, at the New York censor office, they moved all the hands in a batch of clocks intended for shipment, fearing that their position might contain some kind of message.
Sometimes letters were deliberately delayed or altered to prevent supposed secret information from reaching the addressee.
During World War II, American censors "striped" letters to detect the presence of invisible ink. A lab technician would run several brushes, fixed in one holder and soaked in solutions of various developers, over the letter. These developers had different properties and even reacted to human secretions, so that fingerprints and sweat droplets would appear on the paper after treatment.
Local branches of American censorship subjected all suspicious letters to examination, and also randomly checked some of the regular mail. Sometimes, over the course of a week, they would filter all incoming and outgoing correspondence of a particular city. During the war, more than 4,500 suspicious letters were turned over to the FBI. 400 of them were of definite operational value.
In peacetime, the Radio Intelligence Division of the Federal Communications Commission closely monitored the airwaves, which are public property, to prevent violations of existing radio usage rules. During the war, its 12 main and 60 auxiliary monitoring stations, as well as about 90 mobile stations, controlled the entire radio frequency spectrum to detect enemy agent radio stations. These posts and stations were connected to each other via teletype and formed a unified direction-finding system managed from Washington.
At the climax of the war in Europe, the Radio Intelligence Division monitored over 200 frequencies on which enemy radio stations operated and broke most of the ciphers used by German agents in their radio transmissions.
The War with Japan
The Japanese command did not know that the Americans had a secret weapon that could change the situation in the Pacific. This weapon was located in a long, narrow basement room of an administrative building on the grounds of the naval base at Pearl Harbor. There was stationed the radio intelligence unit serving the US Pacific Fleet. At the start of the war, it consisted of thirty officers and enlisted men. Their task was to crack the Japanese naval cipher system, abbreviated as "JN-25A." The name was assigned to it by American cryptanalysts working on breaking this most common encryption system of the Japanese Navy, through which about half of all messages were transmitted.
American cryptographers made a major contribution to the preparation of the operation to eliminate the Marshal of the Japanese Navy, Yamamoto. To ensure the secrecy of the location of the head of the Japanese Navy, Japanese cryptographers chose the current edition of the "JN-25" code, the most common and strong, to shield this information with the "armor" of the cipher. Unfortunately for the Japanese, the "armor plating" of their communication lines was "dissolved" by the caustic "acid" of American cryptanalysis.
The NSA
The NSA owes its birth date to Pearl Harbor. After investigating the circumstances of Japan's surprise attack on the United States, Congress recommended that the US government create a centralized cryptanalytic intelligence service. The recommendation was heeded, and on November 4, 1952, President Truman issued a directive establishing the NSA.
The NSA building became the third largest in the Washington area, after the Pentagon and the State Department buildings.
The NSA reads less than 10% of the total volume of intercepted encrypted material. In peacetime, cryptographers can work more slowly and carefully than in wartime. However, even under wartime conditions, with a huge number of encrypted messages and a much larger number of errors, the German Army Group North read less than 30% of Russian military ciphers. Moreover, NSA interception stations focus their attention on foreign communications of the highest secrecy, which should be best protected, thus lowering the NSA's average success rate.
It is particularly important to note that the American authorities benefit from the location of UN headquarters on American soil. Their arbitrariness has reached such an extent that decrypted instructions from the governments of Iraq, Jordan, Lebanon, Turkey, and Greece to their UN representatives fell into the hands of the State Department before they reached their legitimate addressees.
What can be said about other states? None of them can compete with the United States in the field of cryptanalysis. As always, it comes down to economics. These states cannot place their interception stations around the world. They cannot maintain large cryptanalytic organizations like the NSA, which has the material resources necessary to break modern strong ciphers. In these states, cryptanalysts are more gifted amateurs than professionals.
From the NSA to the Soviet Union
In 1960, an incident occurred that had a "colossal impact on the entire internal security program of the agency": NSA specialists William Martin and Bernon Mitchell defected to the USSR, where they told KGB officers about the agency's work, including the interception of messages traveling along Soviet communication lines. On September 6 of the same year, they held a conference at the Central House of Journalists in Moscow, where they reported that the NSA regularly monitored communications from more than 40 countries, not only Warsaw Pact members but also states considered US allies, such as France.
Statements by William Martin and Bernon Mitchell:
We are extremely concerned about the policy of the United States of deliberately violating the airspace of other countries and the practice of the US government making false statements regarding such violations in order to deceive public opinion. In addition, we are outraged by the US government's practice of intercepting and decrypting the secret communications of its own allies. Finally, we disagree that the US government has gone so far as to recruit agents from among the employees of its allies.
- William Martin and Bernon Mitchell on moving to the USSR:
There, our basic views and interests are shared by the majority of people. Therefore, we believe that socially we will feel better and will be able to work more productively in accordance with our profession. Another motive is that in the Soviet Union, women's talents are encouraged and utilized to a much greater extent than in the United States. We believe this enriches Soviet society and makes Soviet women more attractive.
During an investigation, the House Committee on Un-American Activities discovered numerous security breaches at the NSA. As a result, 26 employees were fired who were deemed sexual perverts, as well as the dishonest deputy director of personnel, Maurice Klein. The latter admitted that in his application he indicated he had graduated from Harvard Law School, while in reality he had graduated from a law school in New Jersey. Klein also said he tried to conceal this and several other transgressions by retyping his personal file and changing dates.
Three years later, another defector, a research analyst from the Middle East department, Victor Hamilton, told the Soviet newspaper Izvestia that the NSA was engaged in cracking the diplomatic codes and ciphers of various countries, as well as monitoring communications at UN headquarters in New York. On June 3, 1959, Hamilton was forced to resign. According to him, his superiors became suspicious when he wanted to re-establish contact with relatives living in Syria. Management, however, believed Hamilton was "on the verge of paranoid schizophrenia" and could not continue serving at the NSA. Whatever the real reason for Hamilton's resignation, he asked the Soviet Union to grant him political asylum and apparently told the Soviet government about his work before writing a letter to Izvestia exposing American espionage activities.
Martin and Mitchell outlined the scale of the NSA's successes. They stated:
The NSA had broken the ciphers of more than forty countries (which was almost half of all the countries in the world at the time Martin and Mitchell made their statement). When asked, "Which countries' ciphers are broken at the NSA?" Martin replied: "Italy, Turkey, France, Yugoslavia, Indonesia, Uruguay. I think that's enough to give a general idea."
- Hamilton supplemented Martin's answer with some interesting details:
I was assigned as an expert to the Middle East sector... This sector dealt with Syria, Iraq, Lebanon, Jordan, Saudi Arabia, Yemen, Libya, Morocco, Tunisia, Turkey, Iran, Greece, and Ethiopia. My colleagues' duties included studying and breaking the military ciphers of these countries, as well as decrypting all correspondence arriving at their diplomatic missions anywhere in the world... The NSA breaks the ciphers of all these countries through cryptanalysis...
Japan
The Japanese Navy tried to find a printing ink that would dissolve in seawater for printing their codebooks, so that when thrown overboard or if the ship sank, the printed text would disappear.
The Japanese relied too heavily on the obscurity of their language, holding the view that a foreigner could not learn the multiple meanings of individual characters firmly enough to know Japanese well. And therefore, they did not worry about the strength of their ciphers.
Cryptography and Commerce
In 1921, Hebern founded the firm "Hebern Electric Code," which became the first manufacturer of rotor cipher machines in the United States. Having received the necessary support from the Navy, and also believing that his invention was the cipher device of the future, he actively sold shares of his company to raise the necessary capital. Since "Hebern Electric Code" held dozens of patents worldwide (among them was not only the patent for the rotor cipher machine, but also patents for many other advanced devices of its time, such as electric typewriters and turn signals for automobiles), Hebern easily sold shares of his company for the astronomical sum for that time of about $1 million. But the enterprise went bankrupt due to low demand.
Hebern, in an ode dedicated to the rotor cipher machine, wrote:
Knight of the radio, guardian of treasures
In July 1923, a corporation was established to produce and market the "Enigma". It was called "Chiffriermaschinen AG" and even during the severe post-war inflation in Germany managed to raise huge capital by selling its shares. Scherbius joined the board of directors of the corporation, which consisted of six people.
Advertising slogan of Chiffriermaschinen AG
One well-protected secret can recoup the entire cost of this machine
In 1916, Gulden and Damm founded the firm "Crypto AG." It was the only manufacturer of encryption devices that remained commercially successful for many years. Among the firm's investors were Emmanuel Nobel, a nephew of Alfred Nobel, who invented dynamite and established the Nobel Prizes, and Caesar Hagelin, a close friend of Emmanuel who worked as manager of the Nobel brothers' oil company in Russia.
The improved version of the "C-36" was greatly liked by the Americans. After testing, it was renamed the "M-209" and was widely used in American military units from divisions to battalions. Royalties to Hagelin, as the patent holder, amounted to millions of dollars. He became the first and only person to amass a multi-million dollar fortune through cryptography.
Cryptanalysis and Art
Not all cryptanalysts served exclusively the god of war, Mars. Some devoted their entire lives to the muse of history, Clio. These little-known workers, whose successes benefited all of humanity, mostly worked fruitfully in the 19th century. It was then, in search of unexplored documents from the diplomatic correspondence of past centuries, that historians rushed into archives whose doors were opened to them by bourgeois-democratic revolutions. To their dismay, scientists discovered that many archival documents were fully or partially encrypted.
Cryptanalysts still have unsolved mysteries, namely the "Voynich Manuscript". It is an illustrated codex written by an unknown author in an unknown language using an unknown alphabet. For over a hundred years, it has not been deciphered.
The mystery of the Mayan hieroglyphs. It was solved with the help of the modern all-conquering weapon of cryptanalysts — the computer. Three Soviet mathematicians — E.V. Evreinov, Y.G. Kosarev, and V.A. Ustinov — were the first to use computer technology to decipher ancient writing. The Soviet mathematicians recorded 60,000 words taken from these texts into the computer's memory. As a result of the calculations, they established that the studied words contain 70 pairs of letters that occur at half of the beginnings of these words. They also found 73 hieroglyphs present at the beginnings of half of the words carved on stones and identified both groups. Then, during a 40-hour electronic "blitz-decryption," the Soviet scientists established similar relationships for the middle and final groups in words. Based on the found relationships, they came to the final conclusion that they had successfully deciphered the Mayan script.
In 1939, a 267-page novel was printed in the United States with modest literary merit, but so original that in its own way it has no equal in the entire centuries-old history of the English language. The very title of the novel points to its uniqueness: "Gadsby — a novel containing over 50,000 words without the letter 'e'." This is a stunning creation. Let the skeptical reader see for himself how long it takes to come up with even one sentence in English without using the letter 'e'. The author had to solve a difficult task at the end of almost every long paragraph: being unable to find a word not containing 'e' with which to end a thought, the author would go back and rewrite the entire paragraph. Wright was so often tempted to use the forbidden word that he had to jam the 'e' key on his typewriter to prevent it from appearing in the text.
The ancient Greek writer Triphiodorus composed an "Odyssey" in which the first book did not contain the letter "alpha," the second "beta," and so on.
Psychology and Cryptology
In cryptanalysis, a morbid state of the human mind most often manifests itself in the form of hypertrophied cryptanalytic activity. Victims of this affliction engage in overly thorough cryptanalysis of completely innocent documents, based on the premise that any text, under an outwardly harmless form, carries secret information. One of the most famous manifestations of this mania was the cryptanalysis of the dramatic works of William Shakespeare to prove that their true author was none other than Francis Bacon.
Cryptanalysis can be viewed as one manifestation of voyeurism. This hypothesis has received support from some well-known specialists. For example, Theodor Reik, an authoritative psychoanalyst, answered the question about the relationship between cryptanalysis and voyeurism: "I am inclined to believe that the drive to break a cipher analytically is based on a continuation of the childhood desire to know what the secret of sexuality is, which parents or adults hide from the boy."
Freud believes that a child strives to learn and acquire knowledge because above all he wants to see the hidden genitals of adults and children. Then cryptanalysis can be viewed as one manifestation of voyeurism. This hypothesis has received support from some well-known specialists. For example, Theodor Reik, an authoritative psychoanalyst, answered the question about the relationship between cryptanalysis and voyeurism.
The voyeuristic hypothesis had its opponents. Freudian psychiatrist Jeptah MacFarlane believes that cryptanalysis expresses only a desire for power: "The cryptanalyst is not interested in the content of cipher telegrams. For him, only the analytical breaking of the cipher matters. He is driven not by petty curiosity or a desire to read someone else's encrypted correspondence, but by pride in his victory over the cipher. The cryptanalyst does not peek through a keyhole. He breaks the door itself."
Unlike Reik, Fromm believes that "the interest in decryption and composing secret codes is to a large extent related to a person's relationship to the outside world, and more specifically, with a feeling of loneliness and the hope that he will find a kindred spirit with whom he could connect... The world is closed to him, and therefore he is forced to decipher what is written not for him."
This explanation sheds some light on the question under study, but it is not much more convincing than other hypotheses. However, if the psychological roots of cryptography and cryptanalysis are not unraveled, their biological roots are clear. These roots go deep into geological epochs, to the simplest single-celled organisms fighting for life in the warm seas of the primordial Earth. Ciphers are protection. For modern man, this is the same as a shell for a turtle, an ink sac for an octopus, camouflage for a chameleon. And cryptanalysis gathers information about the outside world like the ear of a bat, the sensitivity of an amoeba to chemical stimuli, the eye of an eagle. Protection is necessary for self-preservation.
Cryptography Directly
"Human ingenuity cannot devise a cipher that human ingenuity cannot break."
Pliny the Elder, in his "Natural History," written in the 1st century BC, tells how the juice of plants from the spurge family can be used as invisible ink.
One-time pads were not susceptible to cryptanalysis — the cryptanalyst has no starting point for their research, since in a one-time cipher system, the "key" contains no repetitions, is not used more than once, is not connected text, and has no internal structural patterns. Therefore, all decryption methods based to some extent on these characteristics yield no results.
Many cryptographically strong ciphers were not used because of the huge amount of "key" material required. The problems arising from the production, distribution, and destruction of key material may seem trivial to someone not versed in all the intricacies of cipher communication organization, but in wartime, the volume of correspondence often surprises even the most experienced signalmen. In the course of a single day, hundreds of thousands of words may need to be encrypted, requiring the production of millions of key characters. And since the key for each message must be unique and unrepeatable, complications arise.
Cipher machines usually generate key material using one of the most famous random processes — the decay of some radioactive element. A Geiger counter causes such a device to punch a hole in a paper tape whenever the decay exceeds a certain level. Accordingly, a hole is not punched if the decay intensity falls below this level. Thermal noise, which is equally random, is also used.
Cryptography and cryptanalysis are sometimes called twin sciences. Indeed, in practice they complement each other: what one science creates, the other destroys, and vice versa. However, in their nature, cryptography and cryptanalysis differ quite significantly. Cipher work is abstract and extremely theorized. Code-breaking, on the other hand, is empirical and concrete.
A keyboard with an unfortunate selection of letters on the top row — "q", "w", "e", "r", "t", "y", "u", "i", "o", "p" — results in losses of time and money for businesses. Despite the fact that the main workload for most people falls on the right hand, with such a keyboard, the left hand makes more than half of all strokes. It turns out that for typing words like "federated" and "addressed," the left hand frantically darts across the keys while the right hand remains completely idle. Moreover, the two most "hardworking" fingers of the right hand land on the keys with the rarest letters of the English alphabet — "j" and "k." Despite the constancy of letter frequencies and the large difference in frequencies of individual letters in all languages, they are not so noticeable that everyone knows about their existence. One of the people who apparently had no idea about this was Latham Sholes, the inventor of the typewriter, who perpetuated its terrible keyboard. Due to these glaring shortcomings, many other, more successful keyboards were developed. However, all innovations were rejected by typists who didn't want to retrain for a new keyboard, and by firms unwilling to pay for modifying typewriters that had the standard Sholes keyboard.
In cases where inventors and entrepreneurs take into account phenomena related to letter frequencies, they can gain significant additional profit. The most striking example is F. Morse. In 1838, he decided to use an alphabetic signal system for his newly invented electromagnetic telegraph. Morse counted the letters in the type case of a Philadelphia newspaper's print shop and assigned the shortest combinations of dots and dashes to the most frequent letters. With minor exceptions, Morse adhered to this rule when creating his famous code, assigning the shortest symbol (dot) to the most common letter ("e"), another short symbol (dash) to the next most frequent letter ("t"), and so on. When using the modern Morse code, slightly different from his original version, transmitting a telegram of 100 letters in English requires about 940 symbols. If Morse's code had been composed arbitrarily, the same telegram would have required about 1,160 symbols, or roughly 23% more. Thanks to the inventor's insight, which incidentally brought significant financial benefits to his descendants, it became possible to transmit almost 25% more telegrams in a single session than if Morse had composed his code randomly.
Reducing redundancy significantly complicates cryptanalysis. The fact that vowels can be removed from text without much harm provides a simple way of substantially improving almost any cipher system. First, remove all vowels or the maximum possible portion of the message without risking ambiguity when reconstructing its words, and then encrypt what remains.