2. What’s more important is you can reverse engineer algorithm that’s used locally to compare these hashes. Unlike with cloud-based searches other providers run, this puts significant limitations to what Apple or LEA can do on your phone. E.g. they can’t extract strings from PDF or grep through image metadata or request all images of certain users without knowing what these images would depict in advance. The frequency of hash database updates even if opaque will still provide more insight into what is being searched for compared to current status quo where public has zero insights because all search / aggregation queries are run on the server.
