End-to-End Secure Mobile Group Messaging with Conversation Integrity and Minimal Metadata Leakage
Michael Schliep, Nicholas Hopper · 2018
Existing End-to-End secure messaging applications trust a single service provider to deliver messages in a consistent order to a consistent group of conversation members. We propose a protocol that removes this single point of failure by using multiple service providers, enforcing conversation integrity as long as one service provider out of N behave honestly. However, this approach could potentially increase the number of entities that learn the metadata for a conversation. In this work we discuss the challenges and provide a protocol that limits the metadata leakage to that of existing messaging applications while still providing strong conversation integrity.