Comment by daneel_w

We're nowhere near the point where there's any general concern regarding the sizes of 256 bits or 512 bits for hashes, block sizes, key sizes etc. Currently we don't need to consider the problem as a question of what time is required, because we don't have the electrical energy required to explore even a fraction of an unfathomably smaller 128 bit space. We don't have computers that can ingest such power either. "Relax, guy."