It is said that history is written by the winners, but many forget the second part of of that statement, that history is also written about only the powerful and important. The examples of cryptography that survived throughout the ages were those that caused great uproar, such as the beheading of Mary Queen of Scots.
Besides, the common man did not have much need for cryptography before the invention of modern technology. Unless communicating about a potential insurgency plot, most people did not need any form of secret keeping. It was often unnecessary to require a secret address to the nearby woods where their secret stash of gold was buried.
The primary difference between the times then and now, is the amount of information on a person that could be used with malicious intent. Compared to the 16th century, where a person's identity was comprised of a family name, some heirlooms and the land upon which they lived, today every person is a collection of numbers and electronic impulses. Whether it is Social Security, bank account numbers, credit card numbers or even account passwords, today there is every possibility for the threat of theft.
As society continued to advance away from the tyrannical rule of the monarchies that was so well documented in chapter 1, people began to look towards their right to privacy. In the 16th century the only reason to conceal common correspondence was usually an indication that there was something to be concealed in the message. Today however, people use encrypted communication for every day conversations, to ensure their privacy, no matter the message. Electronic communication means that almost any message could be at least intercept, an impossible task with physical messages. The importance of encryption for the common man has grown tenfold.