What do you mean by "brute force" in the context of reversing PII that has been obscured by a one way hash? My IP number passed through SHA1 with a salt (a salt I generated and stored safely on my end) is
6FF6BA399B75F5698CEEDB2B1716C46D12C28DF5
Since this is all that would be sent over the wire for analytics, this is the only information an attacker will have available.
The only thing you can brute force from that is some IP and some salt such that SHA1(IP+Salt) = 6FF6BA399B75F5698CEEDB2B1716C46D12C28DF5
But you'll find millions of such IPs. Perhaps all possible IP's will work with some salt, and give that hash. It's not revealing my IP even if you manage to find a match?
The only thing you can brute force from that is some IP and some salt such that SHA1(IP+Salt) = 6FF6BA399B75F5698CEEDB2B1716C46D12C28DF5 But you'll find millions of such IPs. Perhaps all possible IP's will work with some salt, and give that hash. It's not revealing my IP even if you manage to find a match?