fboemer

https://news.ycombinator.com/item?id=41115179 give some intuition. The server database is stored in plaintext, but the server response will be encrypted under the client's key.

[Disclosure: I work on the team responsible for the feature]

https://developer.apple.com/documentation/sms_and_call_repor... has some more details on privacy in Live Caller ID Lookup.

[Disclosure: I work on the team responsible for the feature]

Swift Homomorphic Encryption implements the Brakerski-Fan-Vercauteren (BFV) HE scheme (https://eprint.iacr.org/2012/078, https://eprint.iacr.org/2012/144) (without bootstrapping). This is a leveled HE scheme, which supports a limited number of encrypted adds and multiplies (among other operations).

[Disclosure: I work on the team responsible for the feature]