I wanted to know 2^24 precalculated keys, is that the maximum precalculated keys that would fit in the hashtable/bloomfilter or could you add more than that?
The only limit is the RAM, near 28-29 bits per element in the bloom filter and some 10 bytes per item in an Array to do binary search, this is near to 14 bytes per item in total.
I say 24 bits of precalculated data and 24 for cracking because the way that the missing characters are distributed in the user example:
e3b0c44****c1c149afbf4c8996fb****7ae41e4649b934c****991b7852b855
My idea is precalculate this part:
**7ae41e4649b934c****991b7852b855 and just brute force the second.
if all the missing characters were together then it can be solved with BSGS in seconds