Cha Chi Bhasha – A Review

Review of the book

“Cha Chi Bhasha – Gupta Sandesh aani Maahitichi Chittathararak Kahaani
(The Story of Codes & Secret Languages)”

by Atul Kahate

Manovikas Prakashan, Pune (India), 2011

ISBN: 978-93-80264-75-2

Nikhil Bhalla,
Cryptology Enthusiast,
Pune (India)


About the author:

Nikhil Bhalla is a cryptology enthusiast with focus on the historical aspects of the field. He completed his Masters in Computer Applications from University of Pune in 2011 and has worked as a software developer with a leading digital marketing agency in 2015.

During his masters’ internship with Dr. D.Y. Patil Science Senior College, Pimpri in 2011, he developed an Anglo-German standalone e-learning program for implementing classical codes and ciphers to facilitate teaching for resident M.Sc. students. During his internship, he presented the poster ClassicCryptJ – E-Learning Platform for Non-Digital Secret Writing at the ‘National Conference on Current Trends in Computer Science & IT’, 2011 and presented the talk ‘Historical Cryptology – An Exploration’ at ‘Zion 11 – A National-level Technical Fest’.

Since early 2013, Nikhil has been contributing to the documentation of the ‘CrypTool’ open-source cryptography e-learning project and has given his testimonial to the project’s web site at cryptool.org on invitation from the project’s chief coordinator. He has maintained a collection of above 3000 information security and cryptography books including rare works.

He has also been a member of the American Cryptogram Association (2012-13).


Contact information:

Name: Nikhil Bhalla
Email Address: nikhil.bhalla07@gmail.com
Postal Address: B-5 103, Mont Vert Pristine, Near Khadki Railway Station, Bopodi, Pune – 411020.
Telephone: 020-25806268


Abstract
The book ‘Cha Chi Bhasha’

Keywords: History of cryptography,

1 Book overview
This book details the history of cryptography and explores the background behind the use of various historical codes and ciphers, especially for people uninitiated to the field.

The author’s purposes in writing the book are:

  • To help the reader explore the history of cryptography right from its origins up to recent developments
  • To ease the difficulty of understanding introductory cryptography from unnecessarily vocabulary-heavy books.

The book’s title ‘Cha Chi Bhasha’, is loosely translated as ‘secret languages’ and refers to a native Marathi language game by the same name. The sub-title ‘Gupta Sandesh aani Maahitichi Chittathararak Kahaanias translated by the author, means ‘The Story of Secrets and Code Languages’ and literally translated, implies ‘The heart-quivering story of secret messages and information’.

As the book title suggests, the book emphasizes on the history of cryptography as an interesting story with all of serious, historic, heart-quivering, even humorous aspects.

2 Book summary

The book consists of 16 chapters followed by a bibliography. The 16 chapters are preceded first by a ‘Prastavana’ by Achyut Godbole and by a preface/foreword (‘Manogat’) by the author (packed in 280 pages?).   

Achyut Godbole in the Prastavana provides an introduction to the contents of the book (with a summary description of each chapter) and advocates the book for both the people who are computer knowledgeable as well as those uninitiated to the field. He ends the ‘Prastavana’ with a mention about his association with the author and his views towards him.

In the ‘Preface/Foreword/Manogat’ section, the author elaborates his first encounter with information security during his first work assignment. He further describes his journey of having written ‘Cryptography and Network Security’ and the story of how the book’s success prompted him to write a book about the history of cryptography. The author ends the preface with a summary of the book, describing it as an interesting read that covers the journey of cryptography from antiquity, covering the First and Second World Wars up to the eras of the telegraph, the computer and the internet.

The book’s chapter titles are:
1. Cryptography and You, 2. The Origins of Cryptography, 3. European Cryptography, 4. The Increasing Gravity of Secrets, 5. Cryptography in the American Revolution, 6. Interesting times with Babbage and Wheatstone, 7. Cryptography during the Telegraph, the American Civil War and Shakespeare, 8. Sensational turn of events during World War I, 9. The Enigma Story, 10. Rejewski’s magic and Enigma’s defeat, 11. Alan Turing & Bletchley Park, 12. Other ciphers of World War II, 13. The (dhamaal) of Public-key Cryptography, 14. The RSA Revolution, 15. Zimmermann & PGP, 16. Quantum Cryptography.

In chapter 1 “Cryptography and You”, the author explains the need for secrets for people of all ages. He describes the concept of phishing and argues human ignorance and error to be the key reasons for compromised security systems. He reasons how every online activity in the internet age cannot do without cryptography. An overview of digitization with respect to mobile communication security is presented at the end of the chapter.

Chapter 2 “The Beginnings of Cryptography” describes the Egyptian origins of cryptography and argues steganography to be the cause of the birth of cryptography.

He further exemplifies steganography with the folklore of the shaved messenger’s head and invisible ink. He then continues to describe the basic model of encryption, and the Caesar cipher followed by an introduction to transposition ciphers and frequency analysis.

At the end of the chapter an introduction to renaissance cryptography is given.

Chapter 3 “European Cryptography” describes the codes and ciphers during the 1600s (1500 – 1599) beginning with the straddling checkerboard cipher, Trithemius’ progressive key cipher and Da Vinci’s mirrored secret writing.

The chapter then describes the secret diaries of Eric Brahe, Harry Byrd, Napoleon and Samuel Pepys and explains the use of codebooks post the cryptanalysis of the monoalphabetic cipher first by Giovanni Soro in Italy and later by Francois Viete in France.

He then harps on the role of Leon Battista Alberti in introducing the first polyalphabetic substitution cipher in 1460’s and describes the Vigenere cipher with respect to its background as well as well as its misattribution to Blaise de Vigenere.

The chapter ends with an introduction to transposition ciphers with simple anagrams, Galilieo’s cipher and Christiaan Huygens’ alphagram.

In chapter 4 “The Increasing Gravity of Secrets” the author explains the background behind the Mary Queen of Scots cipher and story behind her execution in 1586. He then describes the background of the war between the Puritans and the Cavaliers since 1642 and how the decryption of communication between the Cavaliers by Puritan John Wallis led to the execution of the Cavalier head King Charles in 1649.

He describes the rise to fame of Antoine Rossignol around 1628 after he deciphered a Protestants’ message intercepted by the Catholics.

He further describes the attempts of Sir John Wallis to break one of Rossignol’s own ciphers after the latter’s death in 1682. He then describes how one of Sir John Wallis’ decryptions led to England retaining their stronghold in the world politics.

The author then tells the story of how Yin Tang from China, who after losing his property to his elder brother Yin Chen (Verify!) in 1722, got deported to Xining and used the Latin langauge taught to him by a Portuguese named Joeo Murao (Verify!) to communicate secretly with his son. Yin Chen, who had become the king, received Yin Tang’s secret messages and put him and Joe Murao (Verify!) in house arrest in Sicily both of whom died there.

He then explains how In the 17th and 18th centuries, many countries opened ‘Black Chambers’ to provide commercialized services to people wishing to communicate secretly and describes the activities in the ‘Geheim Cabinets Kanzlai’ black chamber. He also mentions the secret service organizations of the time viz. ‘Deciphering Bench’ in England, ‘Cabinet Noir’ in France, ‘Secret Police’ in Russia. Abbot Georgell’s secret parcel to King Louis XV in 1774.

In chapter 7 “The Telegraph, American Civil War, and Shakespearean Cryptography”, the author mentions the 1838 invention of the telegraph by Samuel Morse. He then describes the invention of the Playfair cipher that though attributed to Leon Playfair, was actually invented by Charles Wheatstone who had earlier invented the Rectangular cipher. He further explains how the British government accepted the usage of the cipher after intially deeming it cumbersome.

The author then explains the Nihilists’ attempts to overturn the Czar’s rule in Russia with the help of the Nihilist cipher, attempts that turned futile owing to the efforts of Marx and Lenin.

He then touches upon the frequent visits of American President Abraham Lincoln to American telegraph rooms.

He also mentions how the defector army goofed up during their use of the Caesar cipher with a variation as also the Vigenére cipher during their revolt against the American rule.

The author then mentions the work of telegraph expert Anson Stager who devised a cipher after being called in by the American army to foil the defector army’s plans.

The author then describes the newspaper New York Tribune’s revelations about secret communications during the 1876 presidential elections that indicated that the nephew of Democrat Samuel Tilden was involved in bribing for votes.

He then describes the life and times of Jean Guillaume Auguste Victor François Hubert Kerckhoffs from his birth in Holland in 1835, to his migration to England to improve his knowledge of English, and to his lectureship in advanced language, and after marriage in Latin, Greek, history and Math, to his 1881 book ‘La Cryptographie Militaire’ wherein he addressed encryption both for serious communications as well as for the common man where he prescribed two methods for cryptanalysis, to his appointment as the editor to a committee that promoted John Martin Schleyer’s language ‘Volapük’ and to his death while on vacation in Switzerland in 1903.

The author then describes the life of William Friedman from his birth in Russia in 1892, his study of genetics at Cornell University, his hiring by cloth mercahnt George Fabyan to first assist with his crops and in the cipher department. The author then describes Fabyan’s work in trying to prove that Shakespeare’s plays were written by Queen Elizabeth I’s Lord Chancellor Francis Bacon, especially the finding of the word ‘Bacon’ embedded in the play “Love’s Labour Lost”. He then delves into Friedman’s marriage with fellow cryptologist Elizabeth Smith, his work in Fabiyan’s cipher department, especially the uncovering of a plan by Indian nationalists’ supported by Germany to revolt against the British. The author also mentions Friedman’s witnessing the police firing of an American national accused of selling arms to Indians. The author further mentions Friedman’s inspections of messages received at wireless stations in 1924 suspected to be communications from Mars, given the proximity of the planet to the earth that year.

Finally, the author describes the disastrous outcomes of love escapades involving cryptography citing Kind Edward VIII’s romantic involvement first with Thelma and then with Wallis Warfield Simpson.

In chapter 8 “Sensational Turn of Events During World War I”, the author explains the need for alternative encryption techniques in the 20th century following the breaking of the Vigenére cipher. He further explains drawbacks in the then recently invented wireless technologies simply by having antennas to intercept communications.

The author explains how Russian Czar Nicholas who attacked German-controlled East Prussia ended up losing 30000 soldiers and over a lac soldiers surrendered to Germany as a result of having ignored cryptography to secure their communications.

He then explains how a chance lost by the Allied powers to gain an upper hand over Germany caused by a delay in decrypting German communications caused them to introduce the section ‘Room 40’ specifically for cryptanalysis. The author further mentions how Room 40 helped decrypt communications that hinted to Germany’s plans to attack an English village in January 1915.

The author explains how Germany’s accidental sea attack on Britain instead on America caused Germany’s State Secretary for Foreign Affairs Arthur Zimmermann, as damage control, to join hands with Mexico and assure them the states of Texas, Arizona and New Mexico that Mexico had lost to America during the Mexican war of 1846-47. He further explains how Zimmermann sent an encrypted telegram in this regard on 16 January 1917 to a German correspondent in Washington, who would eventually forward it to the President of Mexico.

The author explains how England’s destruction through its cable ship Telconia of Germany’s most secure wired communications led the former to intercept and decrypt Zimmermann’s telegram.

He mentions how Reverend Montgomery, a German language expert deciphered a blank postcard sent from an unknown address in Turkey to Sir Henry Jones in connection with the latter’s son’s suspected kidnapping where Montgomery decrypted the seemingly unknown sender’s address i.e. “184, King’s Road, Tighnabruaich” by relating the address to ‘First Book of Kings of the Bible that alluded to the line ‘Obadiah took a hundred prophets and hid them by fifties in a cave and fed them with bread and water.’ which meant that Sir Henry’s son was being well looked after by his captors.

The author the explains how Montgomery was appointed by Room 40 to inspect Zimmermann’s telegram, who with Nigel de Grey submitted a partial but substantial decryption to the British Director of Naval Intelligence Admiral Hall, who contrary to Montgomery’s expectations, chose to underplay the matter and kept the decryption to himself than forward it to America. However, Germany’s attack on British navy on 1st February 1917 changed his opinion.

The author explains America’s foray into World War I on April 6, 1917 that came about as a consequence of British head of international affairs Arthur Balfour’s revealing the Zimmermann telegram’s decryptions to Walter Page – America’s envoy in England.

The author then explains how Germany’s allies Austria and Hungary usage of Italy’s cipher ‘CIphoro Roso (Verify!)‘ or the Red cipher to decrypt their communications after they suspended ties with Germany & allies in 1915 caused Italy to face defeat in 1916. Later though, as the author mentions, Italy rapidly improved the security of its communications as a result of which its interactions thereafter remained undeciphered till the end of the war.

The author mentions Dutch Margaretha Geertruida Zelle (1876 – 1917) a.k.a. Mata Hari who, on being appointed by Germany as ‘Secret Agent H-21’ to spy on enemy information, started promiscuous relationships with French and Spain officials. She was arrested by officials after an encrypted message sent to her for a request for money and new assignments was decrypted by Room 40. Allegedly, she appeared unclothed in front of officials who had come to arrest her. Also, before she was executed in 1917, she refused to be blindfolded and was criticized for her revealing attires.

The author then describes a situation wherein a censor altered the message ‘Father is dead’ to ‘Father is deceased’ that received the response ‘Is father dead or deceased?’, given the multiple possible interpretations of the word ‘deceased’.

The author explains how the decryption of the Zimmermann led cipher experts to look for devices to improve security and ease of usage of ciphers. The author then describes Leon Alberti’s cipher disk that used multiple alphabets to encrypt so as to defeat the easy cryptanalysis of the then widely used monoalphabetic ciphers.

The author then describes the French inability to understand Germany’s ciphertext that contained only the letter A, D, F, G and X on March 5, 1918, and how Germany used the same cipher in anticipation of the Battle of Somme. He then constructs an example of an ADFGX cipher using a key to transpose the ciphertext obtained by the ADFGX substitution.

The author then explains how French Georges Painvin (1886 – 1980) decrypted the ADFGX cipher just after Germany reached within 30 miles of Paris, and then soon decrypted a variation of the cipher wherein ciphertexts contained the additional letter ‘V’. The author mentions his role in establishing the Allied nations control over Germany and in establishing one of the biggest pharmaceutical companies.

The author mentions Edward Hugo Hebern (1869 – 1952), who became the first to come up with the idea of the rotors to encrypt messages, became interested in cryptography in his 40s. The author explains one of Hebern’s construction wherein he connected the keys of one typewriter to the levers of another typewriter to emit ciphertext characters depending on the linking between the keys and the levers. The author then mentions an improved version of Hebern’s construction wherein he added 5 drums between the two typewriters, each of which would be able to encrypt a plaintext letter in 16 ways, thus raising the complexity of the arrangement to 265 = 11881365 combinations.

The author explains how Hebern’s first attempts of building a factory in 1921 to sell his cipher machines resulted in only 2 purchases by the Navy, and how it first led to him being summoned in court after his company’s shares dropped drastically. Hebern’s second attempt to sell his cipher machines in Nevada too failed as the Navy severed all business ties with him.

The author explains how Hebern later lost a case he had filed against IBM for stealing his patents, and how his claim for $5crore from the American Navy and Army for having built cipher devices that used his construction resulted in the court announcing $30,000 as compensation that too 8 years after Hebern’s death.

The author then mentions other independent inventors of the rotor cipher machine including Hugo Alexander Koch who patented his invention in October 1919, and German researcher Arthur Scherbius (1878 – 1929) who in addition to his own patent, bought Koch’s patent in 1927. Scherbius, who has studied Electrical Engineering in Hanover and Munich improved Alberti’s construction by replacing the cipher disk with electrical connections, creating a cipher machine that he named as the Enigma machine.

In chapter 9 “The Enigma Story”, the author describes the Enigma machine as a combination of 3 sections – the input section that uses a keyboard to accept plaintext letters, the processing section that after performing various operations on the plaintext characters, converts it into their corresponding ciphertext characters, and finally the output section consisting of bulbs corresponding to each of the alphabet letters that light up according to the plaintext entered through the keyboard. To improve the security of the simple monoalphabetic cipher, Scherbius made the scrambler or rotor advance after obtaining the ciphertext by a factor of 1/26 to ensure different encryptions for the same plaintext character.

After realizing that the action of moving the rotor by a factor of 1/26 could be reverse-engineered, Scherbius introduced another rotor that would move by a factor of 1/26 only after the first rotor’s return to its original position after completion of one full rotation of 26 characters. The cipher machine though would repeat ciphertext characters for similar plaintext after the 2nd rotor’s complete rotation. Still, the Enigma machine ensured quick and efficient encryption via its easy plaintext entry via its keyboard.

To complicate Enigma’s encryption further, Scherbius added a third rotor as well as a reflector that would, on receiving the ciphertext from the rotors, would direct it through them again but in a different, reverse order. The author then explains how codebook would be used to mention the initial position of each of the rotors that, along with an actual Enigma machine, would be required at the decrypting end. The author then mentions the Enigma machine as being a reversible cipher in that the same device can be used to both encrypt as well as decrypt messages.

The author explains that despite it being tedious and time-consuming to individually iterate through all positions of the rotors, multiple people working on it simultaneously would ease the task considerably. Also, an increase in the number of rotors of the Enigma machine would increase the machine’s weight. Scherbius as a security measure, then configured the machine’s rotors to be interchangeable and removable. where three interchangeable rotors could be arranged in 6 ways, thereby increasing Enigma’s complexity to 26 x 26 x 26 x 6 = 52728 possibilities. Scherbius further improved the Enigma by adding a plugboard between the keyboard and the first rotor that would permutate six letters on the keyboard with 6 other letters. The security of the Enigma machine now depended apart from the availability of the machine at the cryptanalyst’s end, but also on the codebook, the order of the rotors as well as the plugboard permutations.

The author then describes the Enigma machine as being 13.5 x 11.6 inches and around 12 kilograms in weight. The author then explains how Scherbius in the light of the Zimmermann telegram decryption, started promoting and selling Enigma machine units on a large scale first to the German army, then to government institutions and railway departments.

The author explains how the next two decades saw the German army buy around 30000 Enigma units. Contrary to expectations of the Enigma giving Germany an upper hand in World War II, it turned out to be instrumental in Hitler’s defeat. Scherbius, who died in 1929 following a buggy crash, did not live to see the day.

The author describes in addition to Hebern, Koch and Scherbius, Arvid Gerhard Damm’s efforts in Sweden to independently invent the rotor machine. The author explains how Damm’s patent application was received in Stockholm just three days after Koch’s application in October 1919 in Holland. The author then explains how Damm along with his friend who he worked for in his textile mill in Finland, had suggested several improvements to the machines used in the textile mills and had also created a device that he installed at his home that could open the door and put on lights. Damm then along with his friend had filed three patents related to cryptography despite Germany’s enmity with England. Damm later started a company to manufacture his cipher machines whose shareholders included the fraternal nephew of the father of the Nobel Prize Alfred Nobel. Realizing that Alfred Nobel’s nephew had invested in Damm’s company, an investor named Hagelin too jumped into the fray.

The author explains how Damm’s attempts to ‘divorce’ a woman who had a fake marriage with, for another woman who he had fallen for, came back to haunt him after his exposure by one of his business partners.The woman Damm had fallen for turned out to be a scamster who fled after getting Damm’s टुमदार home to herself.

The author explains how erroneous constructions of Damm’s attempts in inventing other cipher machines failed to gather attention. The author then describes the story of Hagelin’s son Boris Caesar Wilhelm Hagelin in 1892, who after his engineering, gained experience in candidateship in Russia, Sweden and America and improved Damm’s cipher machine and simplified and beautified it for use. After Damm’s death in 1927, Boris Hagelin took control of his company and sold numerous units of cipher machines that improved Damm’s constructions. In 1934, Boris Hagelin began directing the output of the cipher machine encryptions to a printer instead of the standard light bulbs. Though Boris Hagelin’s machines were heavier by at least 17 kilograms, they could fit in a briefcase and could encrypt 200 characters per minute. For Boris Hagelin to be able to sell his machines to the French army, he reduced their weight to just 1.5 kilograms and ended up 5000 units.

The author explains how Boris Hagelin migrated from Sweden to America across the Atlantic ocean via Berlin and Genova, following Germany’s attacks on Sweden that had caused travel ships to America to be blocked in the light of Hitler’s attacks on France, Holland and Belgium. Boris Hagelin after moving to America imported 50 cipher machines and sold 1 lac 40 thousand units amidst high demand.

The author explains how Boris Hagelin started his own workshop after returning to Sweden from America, but after being forced to shift base to Switzerland following Swedish government’s restrictions over copyrights over his work, Boris Hagelin employed 170 people in Switzerland to help manufacture his machines. When Boris Hagelin died in 1959, he became the only researcher whose invention had a successful business. His Switzerland-based company ‘Crypto AG’ continues to exist today and is even rumoured to supply equipment to around 130 countries under the influence of terrorist organizations.

In chapter 10 “Rejewski’s Magic and Enigma’s Defeat”, the author expains how British researchers in Room 40 continued keeping an eye on German communication after the end of the first World War. The allied nations, despite having decrypted German communications, were circumspect in their ability but were less concerned given Germany’s defeat in the war.

The author then explains how Poland, after becoming an independent and sovereign state after World War I had established ‘Biuro Szyfrów’ a cipher bureau to decrypt communications first from Russia who at their east was eager to propagate communalism, and second from Germany from their west, who were eager to regain territory they had lost to Poland in World War I. Maksymilian Ciężki as the head of the cipher bureau even consulted people with supposed supernatural abilities to help break the Enigma machine.

The author then explains Hans Thilo Schmidt’s work in helping decipher German communications with his birth in 1888 to a professor father and a high-class mother. After working for Germany during World War I, he was ousted from service following to Germany’s defeat and started a soap business which he had to shut down given the economic depression that followed World War I. Hans-Thilo Schmidt’s brother Rudolf Schmidt, who as the head of the Signal Corps had been responsible for the decision to use the Enigma machine, assigned Hans Thilo Schmidt to a position in the top-secret cipher department. However, Hans-Thilo Schmidt started seeking revenge, after being unable to afford to live in expensive Berlin and after realizing that he had been betrayed by his brother as well as his motherland. After refusing (भुलला) a French proposal to divulge German information in lieu of money, Hans-Thilo Schmidt in his meeting with a French agent ‘Rex’ on 8 November 1931 in Verviers, Grand Hotel in Belgium, decided to allow Rex to photocopy two documents regarding the Enigma machine’s operations which would have allowed the French to deduce Enigma’s construction based on its operations. The French without information about the codebook resigned to the task of decrypting Enigma messages.

The author explains how Polish cryptographers at Biuro Szyfrów realized the use of monthly-changing codebooks in the Enigma machine as well as the daily-changing keys that included the plugboard permutations, scramblers’ order and the scrambler settings in the codebook. Germany, realizing the demerits of using the same settings for entire day, introduced a 3-letter key corresponding to the chosen scrambler settings that would be prepended to the ciphertext after being repeated twice after encryption by the Enigma itself. An operator could then decrypt the message key by entering the first six characters of the received ciphertext, revealing the key twice in succession and then use the deduced key to decrypt the rest of the message.

The author explains how the Poles invited 20 mathematicians who were well-versed with the German language under oath of secrecy from the university of Poznań to help decrypt Enigma machines. Marian Rejewski, one of the three people whom Biuro Szyfrów employed, took up a position in statistics given his background in insurance.

Rejewski, without the knowledge of Enigma’s codebook noted that the first and fourth, second and fifth, as well as the third and sixth letters from the first six characters of Enigma’s ciphertext were related to the same plaintext letters. Rejewski then tabularized results about each of the first and fourth, second and fifth, and the third and sixth ciphertext characters corresponding to the same first and fourth, second and fifth, and the third and sixth plaintext character for all the characters of the English alphabet, and then looked for chains formed by relating for instance, a fourth ciphertext character for a plaintext letter to the first ciphertext character for another plaintext letter. Rejewski then searched for similar chains for the second and fifth, as well as the third and the sixth ciphertext characters. After finding such chains for a wide range of ciphertexts, Rejewski deduced that the conversion of letters from the plugboard to the rotors did not affect the number of letters that formed the chains. Rejewski then created a file called ‘catalog’ wherein he mentioned the various letter chains formed for each combination – a total of 1,05,456 that was a consequence of different rotor permutations and rotor settings. Then, for a series of ciphertexts received for a particular day for which Enigma’s settings remained unchanged, Rejewski compared the chains calculated from the received ciphertexts to the chains mentioned in the ‘catalog’ to deduce the Enigma machine setting for that day.

The author explains how Rejewski, despite being initially unaware of the plugboard settings, deduced them by guessing the connections between certain pairs of letters after having decrypted the message independent of the plugboard.

The author then explains Poland’s success in breaking the Enigma being the result of fear of Germany’s attack, the difficulty in solving complex mathematical problems as well as Hans Thilo Schmidt’s revelations.

The author explains how Hermann Göring – Hitler’s successor known for his administration and army accomplishments failed to suspect Poland’s interception of his communications during his 1934 visit to Warsaw. The author explains how Rejewski foiled any further advancements made in the Enigma machine’s construction or its operations.

The author explains how Rejewski, having overestimated the usefulness of the ‘catalog’, in cryptanalyzing the Enigma machine, invented a cryptanalytic machine called ‘Bomba’ that was named so on the ticking sound that it made. The Bomba could deduce Enigma’s key for a particular day in two hours by simulating each of the six scrambler operations using different settings for each scrambler. It was rumoured that Rejewski named the Bomba after a special ice cream he had in a gift shop.

The author explains how Rejewski and his team dedicated themselves throughout the 1930s by decrypting massive Enigma-encrypted communications, ironing errors in the Bomba, and modifying it according to continuous changes to the Enigma.

The author explains how Major Gwido Langer, Rejewski’s head, made him work on all the Enigma codebooks he had received despite the knowledge that it was only required to work on only some of the intercepts, fearing Schmidt stopping the supply of codebooks at the beginning of the second World War. Langer would receive Enigma encrypted messages from French agent Rex who would get 1-2 codebooks from Hans Thilo Schmidt every time they met at deserted locations in the Alps mountains.

The author explains how in December 1938, (rejewskichya kaushalyachya pariseema gaathlya gelya) and describes Germany’s improvements in the Enigma machine by adding two more rotors to the already existing three rotors as well as facilitating choosing any three rotors out of the available five rotors.

The author explains how Rejewski, to counter the new advancements in the Enigma machine, increased the Bomba’s capacity by 10 times and caused the Polish cipher bureau to spend 15 times more than their usual annual budget. Further, Germany’s decision to increase the number of interchangeable plugboard connections in the Enigma machine from 6 to 10 to increase its complexity to (tabbal) 159,000,000,000,000,000,000 took Poland off guard. Also, Hans-Thilo Schmidt ceasing to supply codebooks to Rex led to Langer and Poland missing out on codebooks when they needed them the most.

The author explains how Poland looked towards the Allied nations following Germany’s dissolving of its non-aggression pact with Poland on 27th April 1939 as well as Hitler’s speech against the nation. The author then describes France’s amazement on being shown the Bomba on 24th July 1939 by Gwido Langer after an invitation on 30th June 1939 to French and British cryptanalysts in Warsaw. The French hadn’t expected such a revolutionary advancement from Poland, especially after their view that the intelligence they sent to Poland was inconsequential. The two Enigma machine units that Langer displayed in the meeting with the French and British cryptanalysts were transported to Paris, one of which was later moved to London by hiding it in the luggage of a theater group headed by Sacha Guitry and Yvonne Printemps. Hitler’s attack on Poland two weeks later led to war on 1st September

Hitler’s attack on Poland forced them to stop its cryptanalytic work and move towards the Poland-Romania border. However, Russia surrounding Poland from its other end forced Rejewski and two of his team-mates to enter Romania, where, after being asked to wait by the British envoy in Bucharest, Rejewski and his team-mates, contacted the French envoy fearing their illegal stay in Romania. The French who anticipated Rejewski’s team’s cryptographic assistance, invited them to France with visas. Rejewski’s team under the name ‘Bruno’ in an area near Paris, was asked to recreate the Enigma machine. Alan Turing, a cryptanalyst at Bletchley Park visited the ‘Bruno’ team in 1940 and led to strong connections between Bruno and Bletchley Park.

The author explains how Hitler army’s attacks on France, Holland and Belgium forced Rejewski and his team-mates to move to France. After having started their work on cryptography in France, they again had to be moved to Algeria following France’s (sharangati patkarne) in front of Germany. In Algeria, Rejewski’s team resumed work under the secret name ‘Group 300’. Różycki, one of the group’s youngest members suspiciously died while on a boat journey. Later, the Germany army found Group 300’s whereabouts and confiscated all their literature. Rejewski and Zygalski tried to escape to Britain through Spain, Portugal and Gibraltar, wherein during their journey, they were held and released several times. They finally reached (ipsit sthali) after eight months of journey. In Britain, Rejewski and Zygalski were denied important work by British officials. Close to the end of World War II, after 20000 Polish soldiers claimed base in England, Rejewski was one of 10% who wanted to return to his motherland.

The author explains how Rejewski’s attempts to findn work as a Mathematics school teacher failed after his return to Poland. His health hd deteriorated despite having re-united with his family. The nest year, his 11-year-old son suddenly (dagavla) following which Rejewski began working on useless jobs that included a sales head t a cables manufacturing company, a job in government’s surveillance department and one for a woodcutting company. Numerous articles written about Rejewski in the 1970s brought him in the limelight where he was mentioned in books and TV shows.

The author then mentions a 1904-dated encrypted letter sent to Rejewski in 1976 by a person who was his friend since the second World War, now residing in England. The letter was about a request by the leader of the Polish Socialist Party Józef Piłsudski to Japan to seek help for independence of a large portion of Poland from Russia, who Japan was in war with. Rejewski initialy refused to inspect the letter citing unreadability of some characters in the letter as well some characters being missing. Later, when Rejewski’s friend paid him a visit after being called home by his wife following his strange behaviour and refusal to accompany her for a picnic, Rejewski handed his friend a paper that contained the decryption of the encrypted letter from 1904. Rejewski then clarified that he not be further requested to decrypt messages henceforth.

Rejewski’s team member Zygalski worked as a university professor in England and died in 1978. Two years later, Rejewski, in Poland, died of a heart attack.

In chapter 11 “Alan Turing and Bletchley Park”, the author mentions how England’s Room 40 began recruiting mathematicians, linguists and (shastragnya) following Poland’s decryption of the Enigma machine. The author explains how new recruitments would be directed to Bletchley Park in Buckinghamshire instead of Room 40. With Germany sending over 20 lac wireless messages during World War I, it was estimated that during World war II, 20 lac messages would be sent per day. The author explains how Bletchley Park that could initially accommodate only 200 people, could host 7000 people in the next five years. The author explains how Bletchley Park before (hivala) in 1939 studied Poland’s research on the Enigma. The author explains how Britain with better facilities and financial power compared to Poland, was better equipped for further research on the Enigma machine. The author then explains how the personnel at Bletchley Park attempted to ascertain the daily-changing Enigma keys using which they had deduced information about Germany’s attacks on Denmark and Norway in April 1940 as well as the timing and lcoation of Germany’s bomb attacks on England.

The author explains how Bletchley Park’s cryptanalysts, in addition to Poland’s research, looked to exploit faults in the Enigma machine. The author then explains how despite German Enigma machine operators being instructed to use diferent letters in the message keys, to not repeat message keys in different messages, and to use message keys that could not easily be memorized, they would use adjacent letters on Enigma’s input keyboard e.g. QWE or BNM as messsage keys. Such insecure message keys came to be known as cillies, rumouredly owing to an operator using his girlfriend’s initials CIL as the message key. The Bletchley Park cryptanalysts could then decrypt other Enigma messages that used the same message key.

The author explains how Bletchley Park, boasting of mathematicians, linguists and (shashtragnya) could decode any new advancements made to the Enigma machine, where one of the brightest minds was Alan Mathison Turing.

The author mentions how Alan Turing (1912-1954) had thought very early about computers thinking like humans – a main problem in artificial intelligence. His prediction in 1936 about an intelligent computer coming into existence five decade later came to be true. Alan’s father Julius, who while returning to Britain via sea in 1936 after working in India during its British’s rule, fell in love with and married Sarah Stoney who, born in Madras, was raised in Ireland and its surroundings. Julius having to continue work in India caused Sarah to accompany him to India, leaving a 1 1/2 year old Turing and his four-year old brother in England with a retired colonel and his wife. Sarah, after Sarah’s second return to India, noticed strange behaviour in Alan who now needed a mark on his body to help distinguish between left and right. Despite Alan’s lack of coordination between his limbs that made it impossible for him to shine in sports, he willingly participated in running competetions. Alan would also (chacharlyasarkha), was (totra) and would laugh like (khajil). His attire was (gabalyasarkha). He would postpone shaving his beard fearing the blade’s sharpness, and would faint at the sight of blood. He would wear a gas mask to avoid fever while riding the bicycle. As a solution to the frequent snapping of his cycle’s chain,he invented a machine that notified him just before the chain would snap. He avoided riding vehicles fearing dashing them in case he had an attack.

Alan Turing, despite being dyslexic, couldn’t be treated due to a lack of specialists treating it. Being autistic, Turing’s social skills were underdeveloped and hefound it difficult to befriend people. After his admission to Sherborne school in Dorset in 1926, Turing avoided missing his first day at school following a vehicle (sanp) by riding 60 miles on bicycle over two days during which he halted at night for rest. Alan’s bicycle adventure fetched him a mention in a newspaper. In school, Alan would perform experiments with different chemicals. His ability to read complex mathematical books on one hand, with his inability to barely clear his mathematics examinations was incomprehensible to many.

The author explains how Turing’s friendship with an elder Christopher Marcom opened him up as a result of which Turing suddenly stood first in all subjects in his class. During this time, Turing became aware of his homosexual orientation. After his friend Marcom’s death a few weeks later after he had drunk cow’s milk following a (sansargjanya) illness, Turing was severely affected and lost belief in religion for good. In 1932, Turing, after reading a complex book on mathematics by John von Neumann, wrote a (prabandh) suggesting improvements in Neumann’s (premaya).

In 1936, Turing expressed, contrary to popular belief that there exist some mathematical problems that cannot be solved even by computers. In 1938, he couldn’t get to work with von Neumann after Turing approached him while the latter had come to receive his doctorate in Princeton, America, with Turing himself having to return to England. In 1939, Turing was appointed after the beginning of the second World War in England’s international (doorsanchar) department.

A lot of Turing’s future years were spent in secrecy. He would work at Bletchley Park that was approximately between Cambridge and Oxford. After the war, Bletchey Park soon became a historical building as it was where Turing and his colleagues had foiled Germany’s plans after decrypting their secret communications.

In his efforts, Turing headed the making of a computer known as Colossus, where actually Hugh Alexander managed all responsibilities given Turing’s inability as a manager.

During his time at Bletchley Park, Turing would tie one of his favourite devices. Between 1940 and 1941 when Winston Churchill’s (mitramandal) had formed ‘Homeguard’ as a citizen-based security (sanghatana), Turing became a homeguard solely to be able to learn the rifle. On being held by Colonel Fillingham for skipping routines other than rifling, against the form that Turing had filled during his admission as a homeguard, it came to light that Turing had answered the question regarding his acceptance to follow army rules in the negative.

The British keeping in mind Turing’s intelligence, put him to work to decrypt Germany’s secret communications during the second World War. During his work at Bletchley Park, Turing fell in love with Joan Clarke who had accepted the marriage (maagni) that Turing had given her. Later, despite Turing’s revelations to Clarke about his homosexuality, Joan decided to continue her relationship with him. Turing though,  decided, after a vacation with Joan at a tourist place, that he would not be able to manage both his relationships with his love for Joan. Joan ended up being Turing’s  the only heterosexual relationship.

The author explains how Turing, anticipating Germany’s attack on England, bought silver biscuits in lieu of all his money and hid them in two boxes in a bush near Bletchley Park. Apart from getting a serious backache from his escapade, Turing forgot the exact location where he had hidden the boxes.

Turing met Bell Labs’ Claude Shannon in America during Turing’s visit to the country to decrypt secret communications of an enemy common to England and America. Given Shannon’s work on computers and the (jaal), Turing discussed with Shannon over a wide range of topics.

After the second World War, Turing turned his attention towards his 1936 efforts of inventing a computer that can think like humans. In June 1945, he accepted an invitation to work in National Physical Laboratory (NPL) – England’s largest research institute, to develop a computer called ‘Automatic Computing Engine’ (ACE).

The author explains how Turing decided to revive his interest in running and stood 5th in a (haushi) runnning competition in 1947. Turing’s backaches prevented him from preparing for 1948’s London Olympics. In 1946, described his solution for the Automatic Computing Engine to the NPL, but was rejected given the lack of space required to build the machine as well as lack of (aipat). The NPL then consulted other instututions who refused stating their dislike for both Turing as well as his ideas. Eventually, Turing bid the NPL goodbye in 1948. Though NPL built a computer in 1950, it was very different from Turing’s conceptualization.

In a (prabandh) that Turing wrote on (buddhimatta) and (tarkabuddhi) in 1950, he stated the basis for artificial intelligence and wrote that computers can be proved to think like humans if it is difficult to infer whether the answer to a question came fro ma human or a computer. To test if a device can think, Turing invented a test called ‘Imitation Game’ that later came to be known as the Turing test wherein a person who would ask questions to both a male and a female, who would reply by typing the answer, seated in different rooms. Later, Turing, by replacing the man and woman by a computer, would then test if the answer came from a human or a computer. If ascertaining the source of the answer was found difficult, it would be proved that computers can think like humans. Turing had predicted that, with a 5-minute test, computers by the year 2000 would be able to identify humans from computers with at most 70 percent accuracy. (aalikadchaya expert systems naavachya tantragynaanana turingche bhaakit javaljaval khara tharavle aahe.)

Turing in his attempt to look at different problems coupled with Poland’s inability to counter changes made to the Enigma machine, began efforts to invent a machine that would decrypt messages despite changes to the encrypting machine.

Turing tried to decode new Enigma messages by guessing information about the sender, location, and time from Bletchley Park’s already available collection of decrypted Enigma messages. For instance, an encrypted message received by Bletchley Park just after 6 AM could be estimated to have conveyed weather information, and it could be guessed that the German equivalent of the word ‘weather’ could be a part of the message. Similarly, with the knowledge of the location of different military-related sections that could appear within the original message, Turing would determine the exact location of the guessed words, known as ‘cribs’, and would use them to deduce ciphertext equivalents for those words, and thus eventually the entire ciphertext.

The author explains how Turing developed his own version of the Polish Bomba that was conceptually different from the original Bomba. At the end of 1941, it was still difficult to decipher Enigma messages despite 15 Bombe machines searching for keys using cribs, scrambler settings and more, where it was also tough to ascertain the position of the cribs in the message.

The author then explains how the Allied nations would decrypt Germany’s messages sent on behalf of their allies viz. Italy and Japan, and how the information helped destroy Germany’s (annasatha) in North Africa, as well as how it helped inform the British to remove their troops from Greece after receiving hints of Germany’s attack on the country. Such intelligence also proved to be critical during the Allied nations’ entry into Italy and Sicily in 1943. The author explains how using information from Bletchley Park, the Allied nations ascertained German army’s location near France’s boundaries.

The author explains how the Allied nations would take special care to ensure Germany remained oblivious to their knowledge about Germany’s activities. For instance, on receiving information about the location about Germany’s submarines (U-boats?), the Allied nations would attack only some submarines that too after sending aircrafts to hover over the submarine to indicate to Germany that it was through the aircraft that the submarine had been found, and not as a result of codebreaking.

Germany, who would also spy on the Allied nations, would intercept messages that stated the Allied nations’ spotting of German submarines, but would never know how their own secret communications reached the Allied nations.

The author explains how Britain, on receiving the location of 9 German (maalvaahtuk jahaaj), had instructed their navy to destroy only 7 of them so as to avoid Germany’s suspicion. But after British navy mistakenly destroyed the remaining two ships as well, causing German admiral Kurt Fricke to investigate the matter. Eventually, German investigations hinted at the attacks being a result of natural causes or British espionage, therefore keeping Britain’s Enigma decryptions a secret.

Stuart Milner-Barry, working at Bletchley Park expressed that he hadn’t seen any instance apart from Bletchley’s own decryption efforts where a party had decrypted all of the enemy’s secret communications. It was also believed that Bletchley Park’s successes in decrypting enemy communications helped curtail the length of the second World War. If the war were to continue, the Allied nations would have needed a lot more time and resources to recover from Germany’s attacks and then respond to them. The author explains how Bletchley Park continued to keep information secret after the end of the second World War. Further, they gave the Enigma machines they had gotten from Germany to Commonwealth nations who then used the machine to encrypt their own communications and were promptly decrypted by the British over a number of years.

The author explains how hundreds of people employed at Bletchley Park, after their return to their regular jobs were ordered against revealing any information about their activities at Bletchley Park, and were thus not appreciated as those who fought in the battlefield during the war. A young person who had worked extensively at Bletchley Park was scolded by his school’s headmaster for not having fought in the battlefield, yet could not reveal his role at the institute.

The author then explains how after the second World War, Turing’s colleagues realized his homosexual orientation, but were relieved for the fact that it didn’t come to light during the war, otherwise Turing would have been prohibited from working on the Colossus machine. On Christmas in 1951, Turing fell in love with Arnold Murray, a 19-year old unemployed boy, but soon lost interest and ended his relationship with him after Turing suspected Arnold of theft. One year later, after a theft at Turing’s home by Arnold’s friend Harry in Wilmslow, 10 miles away from Manchester, Turing reported the theft to the police. The police, despite Turing refraining from mentioning Arnold as a suspect, caught hold of him and got him to reveal Harry’s involvement in the theft. Harry, apart from confessing his crime, revealed Turing’s homosexual orientation which led to Turing being booked under indecent and (kaaydebahaaya) behaviour as per British laws. From the two options that Turing was presented – either to serve in prison for a year or to undergo hormonal treatment for his ‘unnatural’ desires, he chose the latter, wherein the large amounts of estrogen injected into his body eliminated his sexual desires, grew women-like breasts and led him to depression. The mental shock that Turing faced got him making medicines that could destroy insects on plants, and (chamchyanna sonyacha mulama ghyaycha prayatna karu lagla). In his experiments, Turing began using Potassium Cyanide and got addicted to making chemicals from home-made (vastu). A man who had homosexual relations with Turing came to meet him in England from Norway, but was held by the police and sent back.

The author explains how Turing on 8th June 1954, just a few weeks before his 42nd birthday was found dead with white precipitate coming out his mouth and a cyanide-dipped apple near him. Despite Turing’s mother’s claims about Turing’s death beingby accident, it was difficult for everyone to believe otherwise.

The author explains how after three decades of secrecy, all information related to Bletchley Park was declassified in 1970 due to the Commonwealth nations ceasing to use the Enigma machine to encrypt their communications, which meant British was no longer interested in decrypting their communications. F.W. Winterbotham, who played a vital role at Bletchley Park, got involved in an intense debate with the government, and released the book ‘The Ultra Secret’, revealing details about Bletchley Park and the Enigma, and bringing to light people who were obscure all this time. Alan Turing though, could not be alive to see the Bletchley Park revelations.

The author explains how Mavis Lever, an 18-year old girl who had learned German from London University and was engrossed in decrypting secret messages from Germany and other enemies on behalf of (mitrarashtraanchya vati-ne), inspected a message sent by Italy’s navy that was devoid of the letter ‘L’. Lever’s suspicion that the original message contained only a series of ‘L’s was found true after the consideration that no letter in the Enigma machine encrypts to itself. It the came to light that Italian navy had sent over a series of ‘L’s just to confuse the Bletchley Park cryptanalysts. Lever then studied how the Enigma encrypts the letter ‘L’ , and also whether such ciphertext has repeated characters or not. Eventually, Lever successfully decrypted Italian secret communications in March 1941 following which the British destroyed Italian (yudhnauka) – an attack that Italy could never recover from.

(Photos, Diagrams, Screen Dumps and Tables)

 (Clarity & Readability)

 

(Type of book)

Teaching/Reference/Methodology/Procedure/Discussion

3 Book style (w.r.t. comprehension, observations and suggestions and inaccuracies)


The book is written in a crisp, story-like fashion with purposeful less focus on technical and terminological aspects so as to be easy for someone new to cryptography.

 

The book’s chapters clearly demarcate each of the phases of cryptography rather well.

 

The book is interspersed illustrations of important personalities and concepts

 

4 Strengths and weaknesses

Strengths

  • The book traces sequentially cryptography’s history and touches upon every critical cryptographic activity from its origins up to quantum cryptography.
  • Conciseness – the book is short yet comprehensive and covers almost every noteworthy cryptographic activity () and method (Caesar, Vigenère, DES, RSA) in merely 280 pages. The author does well to chain together the events in the history of cryptography and present them each as a separate chapter.
  • The language of the book is simple enough for the layman to understand cryptography’s history and its methods.
  • The book is decently illustrated with images of concepts (Schrodinger’s cat, quantum cryptography), people, documents & manuscripts (Mary Queen of Scots, the Zimmermann telegram), ciphers (Vigenère square, Enigma machine) & cipher machines.
  • The concentration on the historical background of the people and methods involved in the history of cryptography makes it interesting for the reader to read further.
  • The author makes it a point to entertain the reader by advertising the book as a story with serious, historic, heart-quivering, even humorous aspects.
  • One of the high points of the book is its lucid explanation of the working and cryptanalysis of the Enigma machine.
  • Though the title and sub-title of the book do not suggest any focus on mathematical aspects of cryptography, the book explains rather well the concepts of ‘’

Weaknesses and observations

  • One feels the book focuses a bit too much on the story and background of cryptography personalities while undermining technical accuracies (substituting codeword for codebook, ) (despite the leeway given as being a non-technical book) and misses out on a few important points – viz. the one-time pad and the Grille cipher.
  • The book relaxes the pronunciations of some of the personalities and methods and terminology described in the book in view of the Marathi language audience viz. .
  • I feel the author takes wanting to entertain the reader a bit too far with some descriptions of promiscuous behavior between cryptography-related people, something that may not go down well with parents of young readers. Despite it being an introduction to new topic for the Marathi audience, there are way a few too many exclamation marks for a non-fiction book where the author somewhat liberally tries to excite the reader by bringing in the personal (sometimes sexual) relations between cryptography-related people into the fray, which may not be suitable for certain age-groups. (48: sundar baaykobarobar maujmajaa karit asey.)
  • The captions at certain places don’t correspond to their respective images.


5 Recommendations

If it could have been, the book could have been slightly better, still it is very comparable to ‘Code Breaking – A History and Exploration’ and

This book stands out for its conciseness and simplicity, and is very apt for any Marathi-speaking person uninitiated to the history of secret writing, more so for a liberal arts student in historical cryptography.  Though the book is as comprehensive as it could have been in 280 pages, it could have focused more on cryptanalysis techniques, but that is rather wishful given the book’s purpose and audience. All in all, ‘Cha Chi Bhasha’ is an engaging, entertaining read.

In conclusion, ‘Cha Chi Bhasha’ has little to complain about, justifies its purpose and audience well and stands out for its conciseness and engagement. The review should help Marathi readers worldwide get interested in cryptography and should encourage Marathi reading liberal arts students in the field to further explore its fascinating history. It compares well with a book by (author) titled (title), and also with..

Indication of figures and tables


References

 

 

Appendices

(Mention how to pronounce “Cha Chi Bhasha”)

 

Given the book is intended primarily for the cryptographically uninitiated, I have reviewed it keeping aside its technicality and terminology.
NOTES:

Description of ‘Cha Chi Bhasha’ game – wherein a word’s first phoneme is replaced by the sound “cha” and the dropped sound is added after the word

(Consider mentioning a bit about the author)

POSSIBLE ERRORS AND NOTES

– Page 108: The author further mentions how Room 40 helped decrypt communications that hinted to Germany’s plans to attack an English village in Jaunary 1915 (Which village?)

– Page 110: Turkistan is in Kazakhstan, whereas Tighnabruaich (where the message was sent from) is in Scotland. Why this discrepancy?

– Page 110: The word spelled as ‘Tighnabrook’ is actually ‘Tighnabruaich’.

– Page 113: Mata Hari’s name is ‘Margaretha Geertruida MacLeod’ and not ‘Margaretta Gertrude Zelle’ (‘Zelle’ was her name when she was born).

– Page 116: The author does NOT mention frequency analysis as the primary reason that monoalphabetic ciphers could be decrypted easily.

– Page 122: The author mentions that Georges Painvin cracked the ADFGVX cipher on January 1, but fails to specify the year.

– Page 123: The author mentions that Hebern was the very first to come up with the idea of rotors to encrypt communications. (But in 2003, it has emerged that the first cipher machine inventors were two Dutch naval officers – Theo A. van Hengel (1875 – 1939) and R. P. C. Spengler (1875 – 1955) in 1915 (De Leeuw, 2003).)

– Page 125: Are scrambler and rotor the same thing, as suggested?

– Page 126: The author fails to mention Arvid Damm as one of the independent inventors of the rotor cipher machine.

Page 144: Hotel Verviers is mentioned as व्हव्हार्येस instead of Verviers.

Page 144: If hans-Thilo Schmidt forgot/ignored (भुलला) the French offer to supply secret information, then why did he meet French agent Rex on 8 November 1931?

Page 144: Maksymilian Ciężki is incorrectly spelled as ‘झायकी’.

Page 152 – 153: The table on Page 153 shows the second character instead of the captioned fourth character as per the four six-letter messages on page 152.

Page 156: The author doesn’t accurately reverse the letter chains at the end of the page.

Page 159: The Bomba (bomba kryptologiczna) that was invented by Marian Rejewski is misspelled across multiple pages as ‘Bombe’. Also, the author fails to mention the name of the ‘Bombe’ machine developed by British cryptologists that included Alan Turing.

Page 162: Sacha Guitry is misspelled as ग्युर्टी (Giurty).

Page 162: ‘PC Bruno’ is inaccurately mentioned as simply ‘Bruno’.

Page 160: In the line “Aadhichya donmadhye teenchi bhar padlyamule ekun paach sankhya asleli..”, the author incorrectly suggests that three scramblers were added to the existing two scramblers, whereas two scramblrs were attached to the exisiting three scramblers.)

Does the book mention ‘MI6’? Did it need to mention ‘MI6’?

Page 161: If the word ‘तब्बल’ means ‘approximately’, then this flaw in the book does not apply. Otherwise, if the author has meant to specify the exact number of possibilities for the Enigma machine, then are the total possibilities for the Enigma machine 159,000,000,000,000,000,000 or is it 158,962,555,217,826,360,000?

(Keep data formats consistent in this document i.e. either ‘April 6, 1917’ or ‘6th April 1917’.)

(Do not use the ‘&’ sign in this document. Use ‘and’ instead.)

(Eliminate the use of shortcuts in the document.)

(Use either UK English or US English, not a mixture of both.)

(Write smaller numbers in words and not as decimal.)

(Replace the use of ‘but’ with ‘however’.)

(Is it ‘lac’ or lakh’?)