If I'm reading this correctly you don't need a specific hash result, just a hash that is less than a specific number. That's much easier to find.
Oh, so it's the hash itself that must be less than a specific value, not the preimage of the hash. Still, that can be rephrased as "inverting any one of the hashes that are below a certain value", which is why I kept mapping it to a hash inversion problem.
And the only known way to do this is to try a large number of bitstrings and see what their hashing yields? Is there a known way to more efficiently search by looking what what bitstrings are likely to have hashes with zeroes in the most significant digits? Could someone improve performance by finding such a method?
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