Projects sharing features with Signal Server

libsignal is a cryptographic library that implements the Signal Protocol, providing the core primitives for end-to-end encrypted messaging with forward secrecy and deniable authentication. It includes the Double Ratchet algorithm for iteratively deriving fresh encryption keys per message, and the X3DH key agreement protocol for establishing shared secrets between parties asynchronously. A session state machine maintains cryptographic state across message exchanges, supporting recovery and out-of-order delivery. The library extends beyond basic messaging encryption with capabilities such as ze

Ockam is an end-to-end encryption framework and distributed identity provider designed to establish secure communication between applications and devices. It provides a secure network overlay that utilizes cryptographic identities and attribute-based access control to implement zero trust network access. The project distinguishes itself through metadata-driven multi-hop routing and a pluggable transport layer, allowing encrypted traffic to move across diverse network topologies without requiring virtual IP overlays. It specifically enables secure tunneling for legacy applications by wrapping

Open-IM-Server is an instant messaging server and cross-platform messaging backend designed for real-time text and media communication. It provides a distributed chat architecture that coordinates user sessions and group communications across multiple server nodes to support millions of concurrent users. The system features a scalable message distribution model that utilizes asynchronous message pipelines and distributed queueing to maintain reliability during traffic spikes. It employs multi-level data caching across local memory and distributed stores to reduce latency and uses a document-b

This project is a decentralized, privacy-focused messaging platform designed to eliminate reliance on central servers and persistent user identifiers. By utilizing a metadata-minimizing protocol, it ensures that all communication remains end-to-end encrypted and that user identities are stored exclusively on the local device. The architecture relies on relay-based message routing and identity-free network addressing to maintain data sovereignty and prevent the correlation of user activity. What distinguishes this platform is its commitment to traffic isolation and anonymity. Each conversation

XMPPFramework is an Objective-C communication framework and networking library used to build instant messaging applications for Mac and iOS. It provides a programmatic foundation for implementing XMPP clients, managing real-time message exchange, and processing structured XML streams between network endpoints. The framework features a modular plugin architecture and extension system that allows for the integration of custom communication capabilities and protocol extensions into the data stream. It distinguishes itself with specialized support for OMEMO end-to-end encryption and a state-based

This project is a messaging SDK for Android applications, providing the core infrastructure for real-time communication using Kotlin and Jetpack Compose. It offers a suite of modular, declarative UI components and a backend-connected API to manage user authentication, persistent socket connections, and data synchronization. The SDK is distinguished by its offline-first architecture, which utilizes local database persistence to cache conversation history and queue user actions for synchronization once network connectivity is restored. Developers can customize the messaging experience through a

Converse.js is an embeddable, self-hosted XMPP chat client that runs entirely in the browser. It communicates with XMPP servers using standard XML stanzas over WebSocket or BOSH transports, and provides end-to-end encryption through the OMEMO protocol with double ratchet algorithm and X3DH key exchange. The client is built on a plugin-based architecture that allows extending core functionality at runtime without modifying the client itself, and uses a DOM-based rendering approach with an event-driven message bus for internal coordination. The client manages message history through XEP-0313 Me

Berty is a peer-to-peer messaging application and framework designed for decentralized private messaging. It utilizes a distributed identity protocol and a decentralized database to enable end-to-end encrypted communication without relying on central servers, phone numbers, or email addresses. The project distinguishes itself through an offline messaging framework that uses Bluetooth Low Energy and multicast DNS for local device discovery. This allows peers to establish direct connections and exchange messages without internet or cellular data, using QR codes for secure contact exchange. The

Jitsi Meet is an open-source platform for real-time audio and video communication. It provides a complete infrastructure for hosting secure video conferences, supporting features such as screen sharing, messaging, and participant polling. The platform is designed for both standalone use and integration into external web or mobile applications. The system utilizes a selective forwarding unit architecture to route media streams between participants, ensuring efficient communication across multiple users. It relies on standardized real-time transport protocols to manage data transmission and inc

Zulip is an open-source, self-hosted chat platform designed for real-time team communication. It organizes conversations into threaded streams, allowing users to maintain focus and manage complex discussions within a private, secure infrastructure. The project provides full control over data, authentication, and server management, making it a comprehensive solution for organizations requiring a dedicated messaging environment. The platform distinguishes itself through a hybrid backend architecture that combines a robust web framework for standard requests with an asynchronous event-streaming

Signal-Desktop is a cross-platform messaging application that provides end-to-end encrypted communication. It implements the Signal Protocol to secure messages and voice calls, ensuring that only intended recipients can access content. The application manages asynchronous key exchange and session initialization to maintain secure communication channels between parties who are not online simultaneously. The project distinguishes itself through advanced cryptographic protections, including hybrid post-quantum security that combines classical elliptic curve cryptography with lattice-based algori

This project is an end-to-end encrypted communication client designed for secure messaging and identity management using public-key cryptography. It provides a cryptographic identity manager to verify authenticity across platforms and integrates a local messaging daemon to synchronize encrypted data and handle network communication. The system features a remote encrypted file system that mounts encrypted storage as local directories for direct file interaction. It also includes automated identity provisioning for registering and authenticating new devices and automation bots using cryptograph

Signal-iOS is an encrypted messaging client that provides secure communication for voice calls, media, and text. It functions as a complete implementation of the Signal Protocol, utilizing end-to-end encryption to ensure that only intended recipients can access transmitted data. The application distinguishes itself through the integration of advanced cryptographic standards, including the use of elliptic curve cryptography for identity verification and digital signature validation. It employs a double ratchet key exchange mechanism to rotate encryption keys for every individual message, ensur

This project is a cross-platform messaging client that implements a secure, real-time communication protocol. It provides a comprehensive development toolkit, including a database library and messaging SDK, which allows for the creation of custom messaging applications that maintain synchronized state across multiple devices. The core architecture relies on an asynchronous event-driven model to ensure responsive performance while managing persistent local database synchronization with server-side state. The client distinguishes itself through a robust end-to-end encryption layer that supports

Signal-Android is an end-to-end encrypted messaging platform designed to ensure that only the sender and recipient can access communication content. The project provides a comprehensive framework for secure, asynchronous message initiation and key agreement, allowing users to establish private channels without requiring simultaneous online presence. It relies on a state machine architecture to manage communication epochs and authentication, ensuring consistent security transitions throughout the messaging lifecycle. The platform distinguishes itself through a hybrid cryptographic approach tha

BitChat Android is a decentralized peer-to-peer messenger that enables communication over Bluetooth mesh networks without requiring any internet connection or central servers. It functions as a full mesh network chat app and a privacy-focused communication tool, with every message encrypted end-to-end using per-session cryptographic keys that ensure forward secrecy. The app operates without accounts or persistent identifiers, resisting user tracking at the protocol level. To strengthen privacy and efficiency, BitChat injects cover traffic to obscure real communication patterns and includes an

node-apn is a Node.js library and push notification driver used to send remote notifications to Apple devices via the Apple Push Notification service. It functions as an HTTP/2 client that manages the construction and transmission of JSON payloads to the Apple notification gateway. The library supports multiple identity verification methods, including certificate-based authentication using PEM or PFX files and token-based authentication with automatically renewing tokens. It includes capabilities for routing traffic through intermediary proxy servers and secure HTTP tunnels to bypass restrict

This project is a comprehensive technical documentation site and reference manual for configuring and deploying WireGuard VPN tunnels and interfaces. It serves as a guide for establishing encrypted network connections between peers using public key authentication to secure data traffic across untrusted networks. The documentation provides specific technical manuals for implementing NAT traversal solutions, including UDP hole punching and the use of bounce servers to connect peers behind restrictive firewalls. It also includes detailed guides on tunnel implementation and protocol references fo

Knuff is a desktop debugging tool designed for testing Apple Push Notification service payloads. It enables the delivery of custom JSON payloads to mobile devices to verify that notifications are received correctly. The application integrates with the system keychain to manage security certificates and private keys for request signing. It also includes a utility to export these security identities from the keychain into portable file formats for use with other development tools. The tool provides mechanisms for automatic device token retrieval and a payload manager to save and reuse device t

Element Android is a decentralized instant messaging application built on the Matrix protocol. It enables users to exchange messages and collaborate across different servers without relying on a single central provider. The application focuses on data privacy and security through end-to-end encrypted messaging, ensuring that private messages and files are only readable by the intended recipients. It supports secure team collaboration via encrypted channels and provides cross-platform chat integration.

go-libp2p is a Go implementation of the libp2p modular networking stack, providing a library for building peer-to-peer applications. It functions as a decentralized application framework that separates transport, security, and discovery layers into pluggable modules for cross-platform interoperability. The library establishes peer-to-peer connections through a modular transport abstraction that supports multiple protocols, while using public key cryptography for peer identity and protocol-agnostic security transports for encrypting and authenticating all traffic. It enables distributed peer d

Mumble is a low-latency voice over IP system designed for real-time communication. It provides a self-hosted, encrypted voice server that secures data transmission using public-private key authentication and digital certificates. The platform distinguishes itself through a request-response protocol for remote configuration and integration with external automation scripts. It also features a graphical overlay that renders active speaker information and chat status on top of other running applications, as well as positional audio to simulate the 3D spatial location of speakers in a virtual envi

PiVPN is an automated VPN deployer and server manager designed to establish secure gateways for remote network access. It provides a command-line tool for the installation and configuration of WireGuard and OpenVPN servers on Linux systems, with specific optimizations for single-board computers like the Raspberry Pi. The project distinguishes itself through a wrapper-based management interface that abstracts complex server commands into simplified operations. This includes automated handling of firewall rules, port forwarding, and package installation, as well as the ability to export client

libp2p is a modular peer-to-peer networking stack designed for building decentralized applications. It provides the core infrastructure necessary for nodes to discover and connect with other participants across a network without relying on central servers. The project distinguishes itself through a flexible transport layer that abstracts multiple protocols, including TCP, QUIC, WebSockets, and WebTransport, into a single interface. It features specialized tools for NAT and firewall traversal, such as hole punching and relay nodes, to establish direct connections between peers and web browsers

rust-libp2p is a modular peer-to-peer networking library written in Rust, implementing the libp2p specification. It provides a composable stack of transport, security, and discovery protocols that can be mixed and matched to build decentralized applications, with a central swarm manager coordinating all active connections, protocol negotiation, and peer lifecycle. The library distinguishes itself through a pluggable transport abstraction that supports TCP, QUIC, WebSocket, WebRTC, and WebTransport, enabling cross-platform operation across browsers, mobile devices, and servers. It secures ever

Ligolo-ng is a network tunneling framework and control server designed for managing remote agents and coordinating network routing. It functions as a reverse tunneling proxy and a site-to-site VPN tool, utilizing a userland TUN interface to pivot network traffic through remote agents. The project distinguishes itself by using a TUN interface routing system to forward TCP, UDP, and ICMP traffic through multiple remote agents. It implements a C2 model where a central server manages remote agents to bypass firewall restrictions and provide direct subnet access to isolated networks. The system c

EasyTier is a decentralized peer-to-peer virtual private network and mesh networking tool. It functions as a layer 3 network overlay that establishes secure tunnels between devices without requiring a centralized server or coordinator. It also serves as a WireGuard-compatible VPN, capable of acting as a server for standard WireGuard clients. The project distinguishes itself through multipath latency-based routing and the use of KCP or QUIC proxies to mitigate packet loss and stabilize connections in high-loss environments. It provides a virtual networking manager featuring a web management co