This week we're talking about number stations. If you watched LOST while it was on the air, you might recognize the idea: radio stations around the world which seem to do little more than spit out a series of numbers every now and then, read by a human voice or sometimes just tones. People have speculated lots about what they're for and what they do. We talk about the stations, as well as some concepts of cryptography that make this old school tech very appealing for information secrecy.