I've been thinking about encryption this morning (and I have no clue why) and I started thinking about if it's at all possible for two strangers to establish a secure connection. I'm having my doubts, but I don't know a whole lot about encryption.
Today, we use SSL to try and establish a secure connection, but it relies on mutual friends of the two strangers (or in other words, certificates and certificate authorities). If the two strangers have no trusted mutual friend, then they can't validate certificates with their trusted mutual friend, and thus can't be entirely sure there isn't a man in the middle.
Is it even theoretically possible for two complete strangers to securely communicate without a mutual friend?