A Secured Parallel Multi-Broker MQTT Framework with Chaos-Enhanced Hybrid Encryption for Repetition-Resistant IoT Security

The proliferation of IoT deployments has exposed critical vulnerabilities in MQTT-based systems, particularly ciphertext-repetition leakage in telemetry encryption, where identical plaintext blocks under a fixed key—common for static sensor readings—collapse ciphertext entropy and expose traffic patterns. We present a parallel multibroker MQTT framework with two encryption variants: a hybrid AES-ChaCha20 cipher (NeoCipher) and an 8D chaotic system-enhanced variant (Chaos-NeoCipher). While AES-128 and base NeoCipher exhibit leakage (entropy falling to 3.9–4.0 bits/byte), Chaos-NeoCipher mitigates it entirely (7.996 bits/byte) through chaotic key schedule advancement on each invocation. Across 100+ nodes, 10 brokers, and five attack scenarios, consensus-based detection achieves near-ceiling performance governed by protocol logic rather than cipher choice. Chaotic tuning via Lyapunov sweep (λ ≈ 0.54 bits/iteration) and batched key-schedule optimization reduce overhead from +39.9 to +17.6%. Our results satisfy key IoT requirements: sub-millisecond cryptographic processing latency (measured as encryption/decryption time only, not including network transmission, broker queuing, or TCP overhead), near-complete detection across five attack classes under controlled simulation conditions, and mitigated single-point-of-failure vulnerability.