I am pleased by the high quality of posts to this question, thank you everyone who participated.
Hello,
Has anyone researched or know why this algorithm was made public? What motives? Important question for Bitcoin
I would say the answer is probably something along the lines of why they made the TOR Project public. If you think something is the best, you want it to be battle tested. That isn’t possible if you keep something secret. Then there’s also the strength in numbers argument. If the NSA is the only one using a certain type of encryption, one can conclude that anything encrypted with that type of encryption was done by the NSA.
But you’re giving enemies the possibility of communicating without being able to tamper with that communication. To what extent is it harmful when you see this type of “encryption” (someone rightfully stated SHA-256 is not an encryption algorithm), you know it’s the NSA?
I’ve read every answer above, and I still think someone should not completely exclude the possibility that they made it public because they have it solved. I think the answer to this question must be something THEY benefit from, contrary to what some suggested above that they’re doing this for being good benevolent people.