Prime Numbers & Cryptography How can two strangers, Alice and Bob, who have never met each other, communicate privately by letter, when they know that all along the route anyone can open the letter and look inside? The answer, explained by mathematician Terence Tao, is beautifully simple: use a box which each party locks with their own lock, and allow the letter to travel back and forth 3 times. Figured it out? If not, the explanation is at 24:50 to 27:38.
Video Lecture: +Terence Tao, Structure and Randomness in the Prime Numbers, UCLA Colloquium Talk, Jan 17, 2007
https://www.youtube.com/watch?v=PtsrAw1LR3E
Terence Tao's blog: https://terrytao.wordpress.com/
A highlights list of what in TT's blog: https://terrytao.wordpress.com/about/