Perhaps an even better introduction to these and related issues is Moxie's famous "changing threats to privacy" talk from 2010/2011--especially the first half h

Perhaps an even better introduction to these and related issues is Moxie's famous "changing threats to privacy" talk from 2010/2011--especially the first half hour: https://www.youtube.com/watch?v=Uxz7r4E2li8 https://www.youtube.com/watch?v=Uxz7r4E2li8 I have pointed many friends--technical and non-technical alike--to Moxie's talk because in addition to some basics of how crypto works, it helps people understand why cryptography is essential to open societies in historical context. The linked essay points out some important basics, but it doesn't really explain why things like the deniability properties of OTR, trust agility for CAs, or perfect forward secrecy are so vital in today's world.