messenger release for the Android platform (the latest version for desktop is , and for iOS — ). The Delta Chat project is noteworthy for using regular email as transport with the ability to translate instant messages into email (chat-over-email, a specialized email client functioning as a messenger). The application code is licensed under GPLv3, while the core library is available under MPL 2.0 (Mozilla Public License). The release is available on Google Play.
Delta Chat does not use its own servers and can work through virtually any email server that supports SMTP and IMAP (for quick detection of new messages, a technique is applied ). Encryption is supported using OpenPGP and the standard for simple automatic configuration and key exchange without using key servers (the key is automatically sent in the first message). The implementation of end-to-end encryption is based on the code , which underwent an independent security audit this year. Traffic is encrypted using TLS in standard system library implementations.
Delta Chat is fully controlled by the user and is not tied to centralized services. Registration on new services is not required, and an existing email can be used as an identifier. If a correspondent does not use Delta Chat, they can read the message as a regular email. Spam is combated through filtering messages from unknown users (by default, only messages from contacts and those previously messaged are displayed, along with replies to one's own messages). Attachments, images, and videos can be displayed.
Group chats can be created, allowing multiple participants to communicate. There is an option to bind a verifiable list of participants to the group, preventing unauthorized individuals from reading the messages (the verification of participants is carried out through cryptographic signatures, and messages are encrypted using end-to-end encryption). Connecting to verified groups is done via an invitation sent with a QR code. Verified chats are currently experimental but their support is planned to be stabilized in early 2020 after the completion of the security audit.
The core of the messenger is being developed separately as a library and can be used to write new clients and bots. The current version of the core library is written in Rust (the old version in C). There are bindings available for Python, Node.js, and Java. In there are unofficial bindings for Go.
Compared to the previous version 0.510.1, the core library has been rewritten from C to Rust without using unsafe code. Support for avatars has been added, and it is now possible to use Delta Chat as a mail client to read regular emails sent without Delta Chat.
Source: opennet.ru
