MPC‐Facilitated Adaptive Security Framework for BFT Protocols

The growing use of blockchain and distributed systems requires Byzantine fault tolerant (BFT) protocols that remain secure under dynamic adversaries. However, existing BFT protocols often rely on static assumptions and lack clear mechanisms to detect and remove malicious or denial‐of‐service (DoS) nodes during execution. We present MBFT, a BFT framework that combines secure multi‐party computation (MPC) with protocol‐level node verification. MBFT integrates ElGamal threshold encryption with an SPDZ‐style preprocessing phase and uses MAC‐based checks to detect inconsistent behavior. It also adopts a hybrid timestamp oracle with off‐chain aggregation and on‐chain validation to support time‐bounded decisions. We specify its trust assumptions and analyze its failure cases within the protocol. Our analysis shows that MBFT maintains safety and liveness under adaptive adversaries, including censorship, internal Byzantine faults, and DoS attacks. Experimental results show that, for a network with n = 32 nodes, MBFT achieves an average per‐round latency of about 0.5 s on desktop platforms, which is comparable to Dumbo BFT under the same setting. The additional cost introduced by node verification remains small, contributing less than 5% of the total latency. In terms of communication, MBFT incurs approximately 27.2 kB total traffic per round, reducing communication overhead by about 50% compared to HoneyBadger BFT and remaining within 4%–6% of Dumbo BFT. These results indicate that MBFT preserves the efficiency of asynchronous BFT protocols while providing explicit support for node accountability.