Secure group messaging protocols, providing end-to-end encryption for group communication, need to handle mobile devices frequently being offline, group members being added or removed, and the possibility of device compromises during long-lived chat sessions. Existing work targets a centralized network model in which all messages are routed through a single server, which is trusted to provide a consistent total order on updates to the group state. In this paper we adapt secure group messaging for decentralized networks that have no central authority. Servers may still optionally be used, but they are trusted less. We define decentralized continuous group key agreement (DCGKA), a new cryptographic primitive encompassing the core of a decentralized secure group messaging protocol; we give a practical construction of a DCGKA protocol and prove its security; and we describe how to construct a full messaging protocol from DCGKA. In the face of device compromise our protocol achieves forward secrecy and post-compromise security. We evaluate the performance of a prototype implementation, and demonstrate that our protocol has practical efficiency.
BeeKEM: Decentralized, Secure and Efficient Group Key Agreement
Group key agreement protocols are essential for modern secure messaging. Most existing group key agreement protocols assume a centralized model with a semi-trusted service that mediates the communication. This is efficient, but problematic for some important applications, since a central service can be a choke point for surveillance and censorship. There is a nascent literature on decentralized group key agreement that avoids such reliance, but existing proposals either do not scale, with update costs linear or quadratic in the group size, or lack proofs of security. Centralized protocols can offer much lower (logarithmic) cost. We present BeeKEM, the first decentralized group key agreement protocol with logarithmic update cost in the common case (degrading to linear in the worst case) and proofs of security. We provide an open-source implementation and demonstrate that it is competitive with OpenMLS. BeeKEM opens the door for a range of communication and collaboration applications offering not only end-to-end encryption, but also metadata privacy and censorship resistance.
An End-to-End Encrypted Peer-to-Peer Chat System with Self-Sovereign Identity
Today, messaging applications are the most popular medium of communication over the Internet. As their use has grown, different security and privacy concerns have received the attention of users. Users consider what they send with others to be private, tamper-proof and secure without getting exposed to unintended entities. Furthermore, users are concerned whether their data is exposed if the service provider encounters any cyber attack. In this paper, we propose a Self-Sovereign Identity (SSI)-based End-to-End Encrypted Peer-to-Peer (E2EE P2P) chat system that does not rely on any specific provider, enhancing user privacy and security. The system leverages decentralized identifiers (DIDs) to establish secure communication channels using the DIDcomm (DID Communications) protocol, which ensures the privacy of user data. We also introduce a secure file sharing mechanism that ensures that all data, including messages, are stored solely on the user's device, further safeguarding user privacy. The system is developed following the Design Science Methodology, addressing probable threats and satisfying different functional and security requirements. The architecture and its implementation details are discussed with the subsequent use cases and protocol flow. Finally, we analyze different aspects of the system.
ATSMS — end-to-end encrypted group messaging
Encrypted group messaging on AT Protocol identities, with no server ordering anything.
White Noise - Secure Private Messenger
A truly secure and private messenger that's lightning fast, massively scalable, and identity-free.
CryptPad: end-to-end encrypted collaboration suite
CryptPad: end-to-end encrypted collaboration suite
CryptPad: end-to-end encrypted collaboration suite
CryptPad: end-to-end encrypted collaboration suite
The Matrix Holiday Update 2022
Matrix, the open protocol for secure decentralised communications
Welcoming Discord users amidst the challenge of Age Verification
Matrix, the open protocol for secure decentralised communications
Room to grow: Building collaborative, open software
We examine one approach to collaborative, open software by building on Matrix, a secure, decentralised, real-time communication protocol with generic database capabilities hiding beneath its current focus on chat.
Making MLS more decentralized
It’s no secret that we at Phoenix R&D are big fans of the Messaging Layer Security (MLS) protocol, having helped it to come into existence. It’s a versatile group key agreement and messaging protocol that’s used to power both asynchronous and real-time applications. MLS is relatively
Keybase Book
Use Keybase for end-to-end encrypted chat messaging, file sharing, and team collaboration. Get the free app for iOS, Mac, Android, Windows, and Linux.
Keybase Book
Use Keybase for end-to-end encrypted chat messaging, file sharing, and team collaboration. Get the free app for iOS, Mac, Android, Windows, and Linux.
Investigation into Message Layer Security (MLS)
This article investigates Message Layer Security (MLS), the IETF standard protocol (RFC 9420) for Signal-style end-to-end encryption. Through a practical analysis of OpenMLS (the Rust reference implementation) and a demonstration CLI chat application (mls-chat), the post reveals the substantial gap between protocol specification and production deployment. Introduction MLS (Message Layer …
Sharing a safety tool: announcing policyserv
Matrix, the open protocol for secure decentralised communications
Decentralized Identity Verification using Zero-Knowledge Proofs: A Privacy-Preserving Authentication Framework
In the contemporary online interaction, digital iden- tity is central, but most systems follow a centralized provider like Google or Facebook. Although convenient, these models pose ma- jor risks to data breach, surveillance, and single point of failure. The proposed paper proposes a privacy-sensitive decentralized identity verification system that uses Zero-Knowledge Proofs (ZKPs) to allow users to make it through claims (e.g., age, citizen- ship, or enrollment) without any personal data being provided, thereby solving the challenges outlined in the paper. Our architecture integrates verifiable credentials, zero-knowledge-SNARKs and an issuer trust registry that is maintained on blockchain smart contracts to guarantee trustless verification and eliminate dependence on centralized authorities. Its system gives its users full control over credentials, allows reuse across applications, and does not expose data.A proof-of-concept implementation has shown the approach to be feasible with Circom and SnarkJS to generate proof, Solidity smart contracts to verify them, and a user interface implemented in React. Results of the evaluations showed that determination of the verification latency is low, the overhead to generate proofs is moderate, and no privacy leakage occurs. It can be used in potential applications such as education, e-governance, healthcare, finance, and online voting.
The Catbird for Bluesky client app now has experimental end to end encrypted group chats. Built using AT Protocol primitives, all you need is to log into Catbird with your Bluesky account. Chat with friends, share images and posts, find your community again. Now available for testing:
Join the Catbird for Bluesky beta
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