Post-Quantum Secure Communication with Multi-KEM Forward Secrecy

The patent segments the cryptographic protocol into multiple independent PQC algorithm instances (first KEM algorithm, second KEM algorithm, third KEM algorithm) that operate in parallel. Each algorithm instance processes its own key encapsulation and decapsulation operations independently, then combines results through a key derivation function. This segmentation allows the system to maintain security through diversity while managing complexity through modular structure.

The patent creates a composite cryptographic system that combines multiple different PQC algorithm types (lattice-based, code-based, isogeny-based) into a unified security mechanism. Rather than relying on a single algorithm type, the system composite multiple algorithm families, each with different mathematical foundations, to achieve security that is resilient against quantum attacks targeting any single algorithm type.

The patent performs preliminary key generation and algorithm selection during the handshake phase before actual data transmission begins. The client and server pre-establish multiple key pairs using different PQC algorithms and pre-negotiate which algorithms to use for the session. This preliminary action ensures that when data transmission occurs, the heavy cryptographic operations have already been prepared, minimizing real-time processing delays.

The patent implements a flexible approach where multiple PQC algorithm instances are available but not all must be actively used in every session. The system can select a subset of algorithms based on negotiated parameters, allowing partial use of the full cryptographic suite. This enables the system to achieve adequate security with fewer active algorithms when possible, reducing computational overhead while maintaining the option to engage more algorithms when higher security is required.

The patent applies local quality by assigning different security characteristics to different parts of the cryptographic system. Each PQC algorithm instance (first, second, third KEM algorithms) can be selected and configured with different security parameters, key sizes, and computational characteristics appropriate to its specific role. This allows the system to optimize each algorithm instance for its particular function while maintaining overall system security through diversity.

The patent prepares multiple independent cryptographic algorithm instances in advance, creating a cushion of security redundancy before any potential compromise occurs. By having multiple algorithm types already established and ready to use, the system ensures that if one algorithm is later found to be vulnerable or compromised, the other pre-prepared algorithms remain available to maintain security. This beforehand cushioning eliminates the need to reactively change algorithms after a vulnerability is discovered.