> Surely Google has something that maps the hashes to actual URL patterns, but like the other commenter said, the partial hash you send is only sent when it mat

> Surely Google has something that maps the hashes to actual URL patterns, but like the other commenter said, the partial hash you send is only sent when it matches a local DB already. It sends the first 4 bytes of a 32 byte SHA-256 hash of the URL. There isn't a reasonable map back for that.