[Cryptography] Bitcoin Question - This may not be the best place to ask

[Mike Tsao]

> Exactly my point.  What's the collision resolution strategy and why isn't
> this a scary proposition?

Steve already implicitly answered this question with the
50%-after-2^80 figure. When the likelihood is that low, a system
doesn't need a collision resolution strategy. Our sun will likely
engulf our planet sooner than the first Bitcoin address collision,
assuming SHA-256 and RIPEMD-160 aren't badly broken before then. If
cryptographic or hardware advances prove that estimate to be overly
optimistic, it's straightforward to update the code to allow longer
addresses based on a wider hash. People can then move their funds over
from the old addresses to new ones.