[brennenHN]

That's actually a really good question that this post wasn't focused on. What's cool about the key pair is that the only information that is passed around is the signature, which is only valuable for a few seconds. The key itself is never transmitted and so it can never be intercepted.

That's a separate problem from the length of cracking, but an equally important one with regards to security.

Also, it would be pretty hard to remember even a single password that long...