Multimodal Cryptography: A Defense-in-Depth Approach to Quantum-Safe Security (Q20a)
The transition to quantum-safe cryptography presents an opportunity to establish a more robust and resilient infrastructure, rather than merely treating post-quantum cryptography (PQC) as a direct replacement for existing methods. While PQC remains susceptible to ongoing cryptanalysis and cannot ensure long-term security guarantees, pre-shared keys (PSKs) offer information-theoretic security assurances. However, PSKs carry significant risks related to forward secrecy (FS) and identity theft if key distribution centers are compromised. This talk introduces the concept of multimodal cryptography, which integrates traditional cryptography with PQC and PSKs to deliver strong end-to-end computational security, even in the event of asymmetric cryptography breaches, while addressing challenges associated with PSKs. The multimodal protocol facilitates the establishment of a shared secret between two entities that can serve as a PSK in existing communication equipment.