They, and more broadly the US defense/intelligence orgs at the time were working on things to enable covert communications and commerce. Such as encrypted messaging apps, and TOR. These tools can be useful for supporting agents.
The NSA had the capability, and the motivation. How plausible is this theory?
There's also the anagram
I AM A HOST TO NSA OK
And this paper from 1996: How to make a mint: The Cryptography of Anonymous Electronic Cash, Laurie Law, Susan Sabett, Jerry Solinas, NSA Office of Information Security Research and Technology, Cryptology Division, https://groups.csail.mit.edu/mac/classes/6.805/articles/money/nsamint/nsamint.htm