Any updates on the additional features for Keyhunt?
Not yet sorry.
All depends on number of missing characters. 12 like in your example is already a serious amount of work.
I agree with that 12 missing characters is a lot of work. And more if there are in different part of the key.
Private key 5KYZdUEo***3FPrtuX2Qb***nNP5zTd7yyr2S******sBCnWjss or
58^12 = 1449225352009601191936
e3b0c44****c1c149afbf4c8996fb****7ae41e4649b934c****991b7852b855
16^12 = 281474976710656
The second key is more solvable that the first one. By the way that kind of examples are rare to be found and most of then are not real.
Perhaps the creator of the keyhunt knows faster algorithms.
With the publickey avaiable for this example we can use BSGS to do this task but we need some changes becasuse we need to do the calculate the differents ranges for each different change in the most significan bytes.
To solve the your hexadecimal key example is only a 48 bits problem.
because 16^12 = 2^48 = 281474976710656
If we do the last 2 missing bytes with BSGS the problem can be reduced to only a 32 bits of forcebrute, this problem can be done/solve in some hours CPU with the correct code.