Mary Queen of Scots made the fatal mistake by not only sending messages through code  that could be broken, but also incriminating herself in the messages by saying exactly her plan. It never occurred to me that perhaps the most important part of making a code is not making a code thats hard to decipher; instead, it is if someone deciphers the code that they still should not be quite sure what the message is talking about. The sender and the receiver of the message should already have decided on certain words set for other words and make the message more ambiguous. Otherwise, if someone can decipher your message, then all of the plans discussed will not be a secret anymore. Had Mary Queen of Scots gave a more ambiguous coded message, once it had been deciphered she still might have been able to complete her plan. Instead she was executed. By reading this chapter in The Code Book by Simon Singh, I have learned that if I am ever in a difficult situation in which I need to pass a code along, it is paramount for me to discuss a separate code with key words to make the message impossible to understand for the reader because almost all types of codes can be deciphered eventually. Coding, ciphering, and deciphering is quite the risk reward business.