pub fn ip_hash(secret: &str, ip: IpAddr, day: Date) -> Vec<u8> ⓘExpand description
What is stored on a crawl instead of the visitor’s address: SHA-256 over a salt that changes every UTC day (derived from the instance secret), then the address. Yesterday’s hashes can’t be matched to today’s, so the counters can’t build a history of a person. IPv6 addresses count by their /64, since a person controls every address in it.