I think that one of the reasons why EN for Android still doesn't have the text encryption feature is that devs didn't figure out where to put it accordingly. But I think that a great place to put it is in the formatting toolbar, because it is already related to selected text. Please don't tell me that you can't code the encryption algorithm in the Android app because it can compute almost anything that a computer does, and in terms of text manipulation it is a piece of cake to do that.