As I read the first chapter of The Code Book by Simon Singh, I found that the ways to protect yourself while making encryptions is what resonated with me most deeply. Obviously, Mary Queen of Scots was not able to cover her tracks and was executed for her participation in a conspiracy that would try to kill Queen Elizabeth. Before taking Cryptography, I had always assumed that encryptions and codes were secure regardless of the strength of the enemy. Now I realize that one had better make sure that they either have a strong communication system or a strong encoding system. However, there are many more things that a code maker can do to protect themselves.
In my opinion, the largest mistake Mary Queen of Scots made was not changing her codes between her and her conspirators. Although changing the key of their encryptions would be a more thorough cover, changing the cipher can be done often and will deter the efforts of any hackers. Simply by putting a number in the text of an encoded message, the receiver would know to shift the numbers in the text to change the message. There are simpler ways to enhance an encryption as well. This could involve intentionally misspelling words to make the message more difficult to decode, but remain legible for the recipient. These changes enhance an encryption and help to protect the sender. There are many more truths I hope to discover in Cryptography.