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> The solution to a puzzle is meaningless if the same solution can be shown as the result of two different inputs. This isn't true. There are an infinite numbe
by DavidHilbert 6y ago
> The solution to a puzzle is meaningless if the same solution can be shown as the result of two different inputs.
This isn't true. There are an infinite number of inputs that result in the same solution for bitcoin (or any hash)
- jl2718 6y agoOkay let’s see an example. ;)
- powerbutton65 6y agoLike it or not they are technically correct. SHA-256 is a one way compression and furthermore the PoW for bitcoin doesn't require a match for the entire hash. There's loads of examples of this in the bitcoin network whenever there's been a fork and eventually orphaned blocks.
- jl2718 6y agoThose are different solutions to the puzzle. Nobody has ever published a sha-256 hash collision. It has happened once with sha-1.
- neolefty 6y agoThe principles are the same — it's just harder to find collisions for larger digest sizes. (Although bugs in sha-1 add an interesting wrinkle to the discussion.) In fact one could argue that encryption without requiring infinite bandwidth or computation requires finite difficulty in math puzzles. So our current approach to encryption is fundamentally vulnerable to (vastly) more powerful adversary computers. Only things like quantum cryptography break free of that limitation, by changing the ground rules.
- jl2718 6y agoAlgorithmic cryptography depends on a computation time approaching infinity for perfect security. Quantum cryptography depends on a data transmission rate approaching zero for perfect security. Either way, perfect security takes forever.
- Moodles 6y agoRight, but that's a little unfair? SHA-256 is literally a function designed to make it impossible to find such collisions. BIONIC problems aren't designed with that in mind.