If we assume uniform sampling for both the blocklist (size N) and the domain to be visited (not in the block list), the collision probability we care about is Pcol(N+1).
The number of existing domains does not matter, only the size of the block list.
Of course when we consider all 401 million domains there will be many more collisions, but in each case we only care about a collision in N+1
If we assume uniform sampling for both the blocklist (size N) and the domain to be visited (not in the block list), the collision probability we care about is Pcol(N+1).
The number of existing domains does not matter, only the size of the block list.
Of course when we consider all 401 million domains there will be many more collisions, but in each case we only care about a collision in N+1