"...one of my specializations was to teach our people at DIA how to keep such information from being compromised even in the highest threat counter-intelligence environments (i.e. China)." Interesting. Is it from a technical/IT standpoint or more of a "social engineering" one? Or a bit of both? That's a genuine question because I really don't know how feasible this type of work could be when done from within the US.
The more logical interpretation is that he doesn't have the decryption keys and has given partial keys to multiple people, thus making his secrets safe from torturing just him.