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A comment on Decades-Old Computer Science Conjecture Solved in Two Pages. Parent comment

Re:Decades-Old Computer Science Conjecture Solved in Two Pages by Leszek on Friday July 26, 2019 @09:19AM (#20534537)
> And I thought they had ways to construct hash functions so that all the inputs of the same length have a different output?

That's trivially impossible for fixed-size hashes, by the pigeon hole principle.

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Re:Decades-Old Computer Science Conjecture Solved in Two Pages by SilasX on Friday July 26, 2019 @11:43AM (#20535606)
Sorry, I meant all inputs whose length equals the output length.

The point being, for at least that case you can guarantee a sensitivity of one bit.

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Re:Decades-Old Computer Science Conjecture Solved in Two Pages by lonelappde on Friday July 26, 2019 @11:00AM (#20535278)
Not if the output is longer than the input, such as for passwords
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Re:Decades-Old Computer Science Conjecture Solved in Two Pages by gitrebase on Friday July 26, 2019 @11:09AM (#20535356)
I doubt any study of hash functions restricts itself to studying a very tiny subset of all possible (infinite) inputs. The security of hash functions is always studied under the assumption of arbitrary inputs.
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