"At the time, the highest security classification was known as Top Secret/Code Word. In practice, the slug — as we called it — 'Top Secret/Code Word' was followed by a noun, so scrupulously chosen that even the most intuitive intruder could not associate a glimpse of the code word with the subject matter it protected. In my day there were a dozen or more of these tightly compartmented classifications of information. Aside from the President and a few others — usually the Secretary of State, Secretary of Defense, and National Security Advisor — no other government official was automatically cleared for 'all source' reports. The lesser recipients of specific code word data had to have a clearly established 'need to know' the substance of the compartmentalized report. Compartmentation, as we called it, is one of the most effective means of protecting sensitive data. Even today, I hesitate to pick a typical code word to illustrate the system. As surely as Heaven gave us little green apples, it would be my luck to pick a five-letter noun that is in current use."