Which jabber client to choose for Android (need PGP/OTR + file sharing)?

Question

Android

Guys, tell me with the choice of the client. Ultimate goal: to establish an encrypted connection between a Windows computer and an Android phone using the XMPP (jabber) protocol. A mandatory criterion is the encryption of all data on the devices of the interlocutors themselves, and not on the server. Also mandatory is the ability to transfer files (also encrypted).
As a client for Windows, I chose PSI + with GPG encryption, as it can transfer files. For the Android client, Xabber works well, but in the last two years they haven't made it possible to transfer files (correct me if I'm wrong). I could not find a suitable solution on my own: I need to transfer any file format; you can install any other add-ons. Tell...
Also the question strongly worries concerning enciphering. I can't fully understand the principle of PGP/OTR. Are messages (or files) encrypted on the user's device or on the server? Or do jabber servers see only encrypted information that is decrypted with a private key already on the recipient's device (through his jabber client) ???

Answer 1

I've been wondering the same thing for the past week. First, I will answer the last paragraph: Encryption occurs on devices, it is called end-to-end, the server does not participate in encryption, which is why OTR, for example, does not allow group communication.
ChatSecure for android allows you to transfer files. True, his interface, of course, is ascetic, to put it mildly. But it fully satisfies your requirements in terms of functionality.

Answer 2

It is important that I be understood correctly, I am not looking for a jabber client that will definitely work on both Windows and Android, but only an android client is needed. Since if both clients use the same XMPP protocol, and both support OTR / PGP encryption, then they should have communication problems. For example, pairing Windows-based Psi+ (or Pidgin) with an Android-based Xabber client should work well. The only problem is that Xabber doesn't transfer files, while Psi+ and Pidgin clients can do it easily. It remains only to find a client for Android.
Is there really no such client in the whole world that would work using the XMPP protocol, encrypt and receive files, an open source client ??? Nowadays, most people use Android devices for a long time, and how to communicate and transfer files to each other over an encrypted channel? Nothing but ChatSecure?

Answer 3

As many as three
https://f-droid.org/en/packages/de.monocles.chat/
https://f-droid.org/en/packages/de.pixart.messenger/
https://f-droid. org/en/packages/eu.siacs.conversations/