Quote from: D҉ataWraith on July 16, 2010, 11:27:46 AM

Wait, what? I thought reversible computation just uses less energy. Where does the non-determinism come in?

It's the theoretical limit of how far you can go with it. When doing a brute force search, you can reverse back to any previous state and try new states.

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Anyway, about the hashing being insecure: Wikipedia says that attacks on SHA-256 still take on the order of 2²⁵⁰ operations. And unless I made a big thinko here, doesn't the hash target change every ~10 minutes? Wouldn't that throw of an attacker? And if it was possible to break SHA faster, wouldn't the system adjust by raising the difficulty level?

It's doubtful that SHA2 would be that broken before all coins have been minted. The issue is it then becomes a question of how much it costs to hijack someone's bank account.