Comment by jjoonathan

Finding such a person would be difficult (but not impossible) for you or for me, but conditional probabilities work heavily in the NSA's favor. They have thousands of in-house people already satisfying 1, 2, and 3. 5 can be perfected by a team and taught to any of those thousands of people and 4 can be achieved with resume tweaking and, at most, a few repeat trials.

It's the same reason why security through obscurity doesn't work: if you chain together 5 obfuscation layers that each keep out 80% of competent hackers, in total they probably keep out 85% or 90% of competent hackers if you're lucky, but certainly not 99.99%, because everyone who bypasses the first layer has a much higher probability of having the skills to bypass the other layers as well.