Without Encryption, No Democracy
Once upon a time, democracy was a fairly simple concept. One of the primary reasons why it worked so well was because people by default had privacy. But with the technological advances of the last fifty years it is clear that things are a bit more complicated. Specifically, privacy is now a concept that is very hard to achieve. And without privacy, we can't have democracy.
I am an in no way the first person to argue that privacy is necessary for democracy. The basic argument goes like this: without privacy you can't have dissent, and dissent is the first part of being able to choose how you are governed. Another aspect is that loss of privacy has been shown to lead to self censorship. So, for a healthy democracy to work, there is an absolute need for some amount of privacy. But with technological advances this is getting harder and harder to achieve.
My suspicion is that privacy in the physical world is a losing battle. But maybe it is still possible in the digital realm. However, this is where cryptography comes in. Without strong encryption, strong digital signatures and strong anonymity, it is impossible to retain privacy on the Internet as well. Thus, we need cryptography for democracy to work in the future.