I'm looking for a lightweight Android app, that:

  1. lets the user choose a file
  2. asks for the password
  3. opens this file and displays the decrypted content in a textarea (scrollable)

However, the app:

  1. should not write the decrypted file on disk (internal or external microSD card) but only displays it,

  2. it should not require network access at all.


  1. the app should use a standardized AES encryption (the input file will be encrypted on PC / Windows, and it has to be read on the phone).

  2. the app should be able to deal with > 300 kB files (so it seems that opening a file in a text editor, Select All, Copy, go in encrypt/decrypt app, Paste won't work, because I noticed that clipboard doesn't seem to support Copy/paste with > 300 kB files).

Also I've looked at this list of apps, and none of them really meets all these criteria.

I'm pretty sure it will be difficult to find an app that meets all criteria, so if there is an open-source app that does most of them, I'll be happy to fork it.

Application: Sometimes I have a big text file (written on PC / Windows), and I'd like to read it (read-only) on my phone.

  • Another one of my lists is about Encryption of Files and Folders – maybe you're luckier with that? – Izzy Nov 8 '17 at 13:29
  • No luck there sadly @Izzy, nearly all apps have > 2 permissions required, and I tried those with only 2 permissions, but they are not exactly what is needed. – Basj Nov 9 '17 at 13:40
  • I've tried to complete those lists, but sadly found no more candidates either. Hopefully someone comes up with what we've missed. Fingers crossed! – Izzy Nov 9 '17 at 14:51
  • Thanks a lot for all you've tried already @Izzy. I'll be happy to write such an open-source app, as soon as I find a solution that allows to write an Android app from my text editor without having to put my hands in a (dirty ;)) IDE :) When this will we working I'll start the encryption app :) – Basj Nov 9 '17 at 14:55
  • LOL another one favoring text mode, huh? Welcome :) When your app is done and does what you want, you can of course put it into an answer (with the appropriate disclosure, naturally). Looking forward to that (ping me then to add it to my lists), good luck! – Izzy Nov 9 '17 at 18:37

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