Since when has evidence of a plausible innocuous explanation ever been enough to lift suspicion of an espionage intelligence operation?

If I was the NSA, the most efficient use of compute power would be to generate an enormous library of innocuous hashes/seeds, then generate my secret key pairs, then find collisions. Call it the No Cloud Of Suspicion Evil Key Generator.

Depending on the exact rainbow table used they wouldn't necessarily be able to recover the original seed generator (that would require more space, and they're already going to be stretching space limits).