Diffie-Hellman is a commonly taught example of how to do this. The video linked above explains it well, but here's a wiki link if you want to read text instead.

Looks like he got sloppy. Paragraphs 33 to 39 in the criminal complaint are of interest here, specifically 34 and 38. Looks like he used the same handle to advertise SR on Shroomery as he did to post a job opening on Bitcoin Talk which was linked to his real email. Of course, this and the Canadian post inspection could both be parallel construction, but that's the official story for now.

From Forbes: "Agents found Ulbricht after Canadian border authorities routinely checked a package intended for his San Francisco home and discovered nine fake identification cards within, which Ulbricht allegedly was seeking to obtain to rent more servers to power Silk Road as it massively expanded." Link: http://www.forbes.com/sites/alexkonrad/2013/10/02/feds-shut-down-silk-road-owner-known-as-dread-pirate-roberts-arrested/

IIRC, in the novel, the zombie outbreak began in a village in China. Looks like it may be time to head for the hills!