In the previous chapter of The Code Book, Singh discussed cryptography during the time of Mary Queen of Scotts. During her time, cryptographers needed to be highly skilled and educated people who spent time dedicating themselves to the art of code breaking. The average person could not decipher encrypted messages. As I mentioned in an earlier blog post, the education level of the average person was very low. An educated person was one who was extremely privileged. Because of this, certain ciphers used during the time were generally not difficult to decode, but still required a specialist.
Cryptography became more widely used after Mary Queen of Scots, which meant that more and more people were learning the art of reading cipher text. Because of this, a more complicated form of cryptography needed to be created. Fortunately, Vigenere cipher was in the process of being perfected. Vingenere ciphers uses two or more alphabets instead of one, meaning each letter is equivalent to two (or more) cipher letters. This substitution cipher could be extremely confusing, which is why keywords were used to assist in discovering the alphabet. The addition of keywords made it so that only the people who had communicated with the author of the text had access to its cipher alphabets.