Hosted by Department of Mathematical Sciences

Title: Post-Quantum Secure Messaging

Invited Speaker: Rolfe Schmidt (Research Engineer for Signal Messenger)

Oct. 7, 2024 from 5:30pm - 6:30pm in AFLS E107

Abstract:

How can we be confident that our communications will be secure in a world with cryptographically relevant quantum computers? We start answering that question by looking at security in the pre-quantum world, examining the Signal Protocol - a protocol used to protect the communications of billions of people worldwide today - and how it uses a set of well understood cryptographic primitives to provide a suite of security features including mutual authentication, forward secrecy, and deniability. Unfortunately, these primitives  can be broken by a quantum computer capable of executing Shor's algorithm at scale.

To address this there has been extensive research in developing alternative primitives that remain secure against quantum attacks. We will see how Signal Messenger has updated the Signal Protocol to begin providing post-quantum security, how they are using machine verified proofs to confirm protocol security, and what work still needs to be done at the level of primitives and at the level of protocols to fully prepare our security infrastructure for a post-quantum world.

About the Speaker: At Signal, Rolfe identifies relevant security research and helps bring it into production. He was a main contributor to the post-quantum PQXDH protocol, is actively working on new post-quantum messaging protocols, and has contributed to projects including Signal's ORAM-backed Contact Discovery Service and Secure Value Recovery system.