Architecture: Microservice
Language: Golang
Database: Mysql (you can switch to another SQL server, for example Postgres)
Connection Type: https, websocket
Calls: webRTC
Encryption of all data: AES256, RSA.
Channel Encryption: SSL / TLS 6.
Monitoring: grafana / influxdb

Integration with Active Directory user management system is provided

Development Language: C ++ / QT
The application uses QML to render the interface.
The QT library used for development allows you to develop one application at once on 3 platforms: Windows, MacOS and Linux.

There is a separate user management application when integrating with Active Directory.

Applications for iOS and Android are written in the "native" languages – Swift and Kotlin, respectively.

A universal mobile application development on Flutter / Dart. This technology is convenient in that it allows you to make one application that will work on two platforms at once: iOS and Andoid.

Authentication. Mandatory user authentication when connecting to the server. The server uses its own user password hash and authentication protocol.

To prevent theft and spoofing of a session, each user session is one-time (sessions are protected by one-time keys). If the server detects a second connection with the same session, it disconnects both sessions and offers to log in again.

Multi-factor authentication. It is used both to confirm the identity of the user, and to authenticate the interlocutor.

Cryptography. End-to-end encryption technology based on AES, and SHA-512 algorithms. Not only the data transmission channel is encrypted, but also all transmitted information: text, voice, files.

The RSA algorithm is used to encrypt / decrypt group keys.

OTR. Off-the-Record Messaging. A cryptographic protocol that provides the ability to set additional password encryption for correspondence with a specific user

Integrity Monitoring of the transmitted information. The system controls the sending / receiving of all packets, reducing the possibility of MITM attacks on the system.