What Vern said is a misnomer. Binary is simply a counting system comprising of 2 different digits. Its base 2, whereas the system we use is base 10. To "know" binary means you can count in it, which is no large feat.
What Vern meant is he needs some on who can read machine code. That's pretty hard. Few people can anymore because of the prevalence of compilers. Since you cant pull the source code out of a compiled file you have to look at the assembled machine code. You do this with a hex editor. It's actually a very simply process, the problem is, assembly is very archaic and hard to understand by all but the people who made it.