SHEG: A Self-Healing Encryption Graph for post-quantum hybrid encryption with robust fault and DFA resilience

Recent developments in post-quantum cryptography (PQC) have brought quantum-resistant algorithms like Kyber512. Nevertheless, the current hybrid encryption systems incorporating the combination of symmetric encryption and PQC primitives are still susceptible to fault injection and differential fault analysis (DFA) attacks. In order to overcome these issues, SHEG introduces a fault-resilient execution framework for hybrid post-quantum cryptographic primitives, modeling AES-GCM and Kyber512 operations as a self-healing execution graph with node-level verification and selective rollback recovery. SHEG combines AES-GCM for high-speed symmetric encryption with Kyber512 for quantum-secure key encapsulation, and models the encryption flow as a directed graph with chained integrity checkpoints. This architecture supports real-time fault detection and selective rollback recovery, recomputing only the affected execution stages. As a result, rollback cost is reduced by up to 75% when faults occur in later execution stages. Experimental results demonstrate that SHEG provides execution-level fault resilience against practical DFA-style attacks under the stated threat model, achieving a recovery rate exceeding 99% at a 1% fault injection rate while introducing only approximately 10% computational overhead. SHEG provides execution-level fault resilience with moderate computational overhead. However, additional evaluation on embedded and resource-constrained platforms is required to assess deployment-specific performance characteristics.