This post relates to the preceding "Web of Trust" post. I'm putting my Public Key on the Internet in multiple places, where people can access it and see that it is the same data in those different places --and where, presumably, only I had the ability to post that data in all those places. At this writing the data can be compared at this site and this site, and
Think about the number of different sites you typically visit, and the number of sites where you joined to become someone who could post some sort of content. You've probably used different passwords at those sites, which means that, in general, you are the only person who is able to access your accounts at all those sites. Now suppose you fired up a "Pretty Good Privacy" program like "GnuPG", and created a Private Key (that you keep secret) and a Public
The preceding relates to another thing, the quantum-mechanical mechanism for interfering with the actual speed of light. Those pairs of virtual particles that form also have mass. That means, while they temporarily exist, they also cannot be traveling at exactly light-speed; they have to be traveling slightly slower.