K-Waay: Fast and Deniable Post-Quantum X3DH without Ring Signatures

Learn about a groundbreaking security protocol presentation from USENIX Security '24 that introduces an efficient post-quantum alternative to the X3DH key exchange protocol used in messaging apps like WhatsApp. Explore how the proposed K-Waay protocol achieves quantum security without relying on ring signatures, while maintaining crucial features like asynchronicity and deniability. Discover the innovative use of split-KEM primitive and its implementation based on the Frodo key exchange protocol, offering significant performance improvements over existing solutions. Understand the theoretical foundations, security proofs, and benchmarking results that demonstrate K-Waay's superior efficiency even with conservative parameter choices and plain LWE assumptions.