. Communicating a secret between strangers is one of the towering intellectual achievement of modern cryptography. The solution to exchanging secrets between strangers is indispensable to life in the global village where strangers deal and transact, like in the physical town square. The technology is only possible in the category of eroding intractability encryption. To understand the feat of this technology, we may want to first appreciate the challenge and the need for it, then follow on the initial attempts and track the intellectual pathway to today's tools that enable sharing secrets among strangers.