Jeez, I was in ASA/NSA for 4 years. I was rated TS/Codeword/Crypto (orange badge). There was little need. Most of what I handled was so heavily encrypted I knew nothing about what it meant. Maybe where the info came from was really secret. I was once congratulated on some info I had gathered. Due to the time and area where gathered I had a bit of an inkling what that one was about.
One funny thing, I was naturally debriefed when I got my separation orders. I can't remember any of the codewords that were current at the time, but I can remember some of the old unused codewords.
BTW, someone above who mentioned the different levels left out CONFIDENTIAL. Is it not used anymore?