So, searching through encrypted text is a really interesting problem! It's actually possible under some ciphers / search algorithms - if the client generates e

So, searching through encrypted text is a really interesting problem! It's actually possible under some ciphers / search algorithms - if the client generates encrypted inverted index entries when submitting a post, and encrypts their (vectorized) search query using the same key, the server can compare them and return a scored list of IDs. You do need to weaken the encryption scheme somewhat - in particular, term-frequency analysis becomes possible.