Summary of Simon Singh's The Code Book

By IRB Media

Please note: This is a companion version & not the original book. Book Preview:

#1 On October 15, 1586, Queen Mary of Scots was on trial for treason. She had been accused of plotting to assassinate Queen Elizabeth in order to take the English crown for herself. Sir Francis Walsingham, Elizabeth’s Principal Secretary, planned to prove that Mary was at the heart of the plot, and was therefore equally culpable and deserving of death.

#2 The plot to kill Elizabeth and replace her with Mary, a fellow Catholic, was discovered by Walsingham, the principal secretary. The challenge for him was to demonstrate a link between Mary and the plotters.

#3 The art of secret writing was used to save Greece from being conquered by the Persians in 480 B. C. The long-running feud between Greece and Persia reached a crisis soon after Xerxes began constructing a city at Persepolis, the new capital for his kingdom. The Greeks began to arm themselves.

#4 The ancient Chinese wrote messages on fine silk, which was then scrunched into a tiny ball and covered in wax. The messenger would then swallow the ball of wax. In the sixteenth century, the Italian scientist Giovanni Porta described how to conceal a message within a hard-boiled egg by making an ink from a mixture of one ounce of alum and a pint of vinegar.

• Language: English
• Publisher: IRB Media
• Release date: Apr 23, 2022
• ISBN: 9781669393948

IRB Media

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Insights on Simon Singh's The Code Book

Contents

Insights from Chapter 1

Insights from Chapter 2

Insights from Chapter 3

Insights from Chapter 4

Insights from Chapter 5

Insights from Chapter 6

Insights from Chapter 7

Insights from Chapter 8

Insights from Chapter 1

#1

On October 15, 1586, Queen Mary of Scots was on trial for treason. She had been accused of plotting to assassinate Queen Elizabeth in order to take the English crown for herself. Sir Francis Walsingham, Elizabeth’s Principal Secretary, planned to prove that Mary was at the heart of the plot, and was therefore equally culpable and deserving of death.

#2

The plot to kill Elizabeth and replace her with Mary, a fellow Catholic, was discovered by Walsingham, the principal secretary. The challenge for him was to demonstrate a link between Mary and the plotters.

#3

The art of secret writing was used to save Greece from being conquered by the Persians in 480 B. C. The long-running feud between Greece and Persia reached a crisis soon after Xerxes began constructing a city at Persepolis, the new capital for his kingdom. The Greeks began to arm themselves.

#4

The ancient Chinese wrote messages on fine silk, which was then scrunched into a tiny ball and covered in wax. The messenger would then swallow the ball of wax. In the sixteenth century, the Italian scientist Giovanni Porta described how to conceal a message within a hard-boiled egg by making an ink from a mixture of one ounce of alum and a pint of vinegar.

#5

The aim of cryptography is not to hide the existence of a message, but rather to hide its meaning. To render a message unintelligible, it is scrambled according to a particular protocol that is agreed beforehand between the sender and the intended recipient.

#6

Cryptography can be divided into two branches, called transposition and substitution. In transposition, the letters of the message are simply rearranged, which effectively generates an anagram. For very short messages, such as a single word, this method is relatively insecure because there are only a limited number of ways of rearranging a handful of letters.

#7

Transposition is another form of encryption. It is when a message is written along the length of a wooden staff, and then the strip is unwound, which reveals a list of meaningless letters. The message has been scrambled. To recover it, the sender's scytale must be used.

#8

The first documented use of a substitution cipher for military purposes was by Julius Caesar, who sent a message to Cicero, who was besieged and on the verge of surrendering. The substitution replaced Roman letters with Greek letters, rendering the message unintelligible to the enemy.

#9

The Caesar shift is a method of encryption that involves substituting each letter in the plain alphabet with a letter from a cipher alphabet, and the cipher alphabet is allowed to consist of any rearrangement of the plain alphabet. The key defines the exact cipher alphabet to be used for a particular encryption.

#10

A secure cipher system must have a wide range of potential keys. For example, if the sender uses the Caesar shift cipher to encrypt a message, then encryption is relatively weak because there are only 25 potential keys. From the enemy’s point of view, if they intercept the message and suspect that the algorithm is the Caesar shift, they only have to check the 25 possibilities.

#11

The substitution cipher was the first method of secret writing to be developed, and it remained the most secure method for centuries. However, codebreakers would eventually find