Well, on those feet, I'd ask for money, not knowledge. That has the advantage that the NSA may actually accept the deal, instead of just blackmailing me (or worse).
That is, if I wanted to make any kind of deal with the NSA.
Why would you expect a lawless organization like this to actually pay you?
It might just be easier for them to say "Thanks, but we already knew that, and by the way that's ultra classified so we'll give you the option of a clean suicide."
The money isn't the issue. The issue is that once you disclose the algorithm, your continued existence can then only represent future nation-state levels of liability.
The NSA is but one of several massive spy operations under the Pentagon. It's not even the best funded. Several of them are ones most people have never even heard of. I'd say that qualifies as 'faceless'.
That is, if I wanted to make any kind of deal with the NSA.