aTalk (Jabber / XMPP)

This application is a secure instant messaging platform that allows users to communicate with each other through plain text messages. It offers end-to-end encryption using either OMEMO or OTR, ensuring that all conversations are private and secure. The app also utilizes SSL certificates, DNSSEC, and DANE for secure connection establishment, providing an extra layer of protection for users.

One of the key features of this app is its ability to share media files using OMEMO encryption. This means that users can share any type of file, including documents and images, with the added security of encryption. The app also has a fault-tolerance file transfer algorithm, making it easy to share files reliably.

In addition to file sharing, the app also supports unread message badges in the contact and chat room user interface. Users can also set their own quiet hours, where they will not receive any notifications from the app. The app also has text-to-speech and speech recognition capabilities for chat sessions.

The app supports various XMPP extensions, including Last Activity time associated with contacts, bookmarks for conference rooms, and verifying HTTP requests for user authentication. It also has features such as chat state notifications, BOSH with proxy support, and the use of SASL EXTERNAL with TLS certificates for authentication.

Other notable features of this app include message delivery receipts, support for unattended and attended Jingle call session transfers, and message archive management. It also has a built-in demo for GPS-location features, allowing users to send their location to a desired contact for real-time tracking or playback animation. The app also has a 360° street view feature for self-guided tours and an integrated photo editor for avatar customization. With support for multiple accounts, dark and light themes, and multiple languages, this app offers a comprehensive and secure messaging experience for users.