Most of the call spam blocking solutions suffer from needing to trust Caller ID. Spoofing caller ID is now trivial and used by spammers [1] There are some work

Most of the call spam blocking solutions suffer from needing to trust Caller ID. Spoofing caller ID is now trivial and used by spammers [1] There are some work arounds to this like "audio fingerprinting". [1] https://en.wikipedia.org/wiki/Caller_ID_spoofing https://en.wikipedia.org/wiki/Caller_ID_spoofing