Local Inbox/Sent/Archive/Contacts search (in-app within encrypted indexed text).
Locally index emails and contacts, and search them by key words/text.
Yes, except that I'll like to be locally & encrypted (within the
App). I do not know about the the other requirement you've posted in your reply. If it's same, then it'll be great!
Colin Arnott commented
This sounds like a duplicate of https://tutanota.uservoice.com/forums/237921-general/suggestions/6724234-build-in-search