Storing email as ciphertext makes it awfully hard to search. You really want to store it as plaintext on a computer that you control. Historically that meant

Storing email as ciphertext makes it awfully hard to search. You really want to store it as plaintext on a computer that you control. Historically that meant your client computer. Storing email on servers (even your own) seems like asking for trouble, though it can work if you control the server and are careful enough.