I thought was going to be about submarines.
Same.
More on topic though, the Naval Academy has been using "Alpha Codes" for as long as anyone seems to be able to remember. Our emails are M (presumable for "midshipman")+(last two digits of class year)+(4 Random Numbers)... I would think the DoD could use a similar system where they do NAO (Naval Officer) +(Year of Entrance) + (Random Numbers) and differentiated by service, so like AFO for Air Force Officer, ARE for Army Enlisted, and so on and so forth. We memorize our Alpha Codes a million times during plebe summer, so it's embedded in you from the get go and I imagine that any other indoctrination program could find a way to incoporate it as well.
Just my .02.