you say we could calculate a specific search space when we know the pub key from these addresses.
but why are the BTC still there ?
is it also impossible with the specific search space ?
We can't "calculate" a specific search space, we need to know the specific search space before starting the computation. That's the reason why those btc are still there, because nobody (except the btc owner) knows the specific search space for those private keys.
OK so the possibility that the addresses are in the 250 - 256 space is high.
When we take one of these space and make this with the baby step giant step?
Or do I understand something really wrong?
Each is double what is was before.. so imagine the memory needed for such a thing. Let's say (arbitrary example- not real) it takes 8 gb ram to do giant step 1 >>> 28 then 29 would be 16 gb ram 30 would be 32 .. --> 40 would be 32 terrabytes ram ---> 50 would be 32 PETAbytes of on board ram... etc.... so you can see where the issue lies.