Indeed. The client could maintain a vector search table that contains "unencrypted" data from emails, but the table itself could be separately encrypted on-devi

Indeed. The client could maintain a vector search table that contains "unencrypted" data from emails, but the table itself could be separately encrypted on-device to the same level of security as the rest of the iPhone/MacBook/etc (T2/TPM/HSM chip). Definitely a client problem.