6 ms·

That's only relevant if you're using it to make signatures, thus you can make two inputs that hash to the same digest, and signing that digest creates a signatu

by dnet 7y ago

That's only relevant if you're using it to make signatures, thus you can make two inputs that hash to the same digest, and signing that digest creates a signature that's valid for both inputs. In this case, the only threat model might be brute forcing the answer, but that applies to SHA-2 as well, since both are designed to be fast so that you can hash gigabytes in reasonable well. For that, something memory-hard such as Argon2 should be used.

shakna 7y ago
> That's only relevant if you're using it to make signatures, thus you can make two inputs that hash to the same digest, and signing that digest creates a signature that's valid for both inputs. It looks to me like they're just checking hashes, so if you have a collision, you can game it: > The answers are the MD5 hashes of correct lower cased answers: you should be able to check responses from real users you challenge with the question against these checksums.