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A comment on How easy is it in 2022 to find a SHA1 collision?. Parent comment

Re:How easy is it in 2022 to find a SHA1 collision? by omginternets on Monday April 25, 2022 @08:23AM (#31153452)
> You simply cannot fit a larger set in a smaller set.

Just restating this in a different way: hash functions are surjective.

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Re:How easy is it in 2022 to find a SHA1 collision? by remram on Monday April 25, 2022 @08:39AM (#31153586)
That's not what this means and in fact they might not be. It is possible for a hashing functions to have no input that leads to a particular hash (it would still be a hashing function).
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Re:How easy is it in 2022 to find a SHA1 collision? by dasyatidprime on Monday April 25, 2022 @09:20AM (#31154144)
I believe you mean “hash functions are not injective”.
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Re:How easy is it in 2022 to find a SHA1 collision? by omginternets on Wednesday April 27, 2022 @12:04PM (#31181773)
Yes, thanks for catching that.
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