Broadly, an end-to-end encrypted messaging protocol is one that ensures that only the participants in a conversation, and no intermediate servers, routers, or relay systems, can read and write messages. An end-to-end encrypted group messaging protocol is one that ensures this for all participants in a conversation of three or more people.

End-to-end encrypted group messaging is a necessary problem to solve. Whether it be for limiting liability, providing verifiable client-side security, or removing a single point of failure, there are good reasons for a group messaging host to use an end-to-end encrypted protocol.

Michael Rosenberg