Byzantine Fault Tolerance in Practice

BFT handles malicious nodes in distributed systems. Required for trustless networks but computationally expensive.

PBFT Algorithm

```python class PBFTNode: def execute_pbft(self, request): # 1. Pre-prepare if self.is_primary: self.broadcast_preprepare(request) # 2. Prepare (wait for 2f+1 matches) if self.collect_prepare_votes() >= 2self.f + 1: self.broadcast_commit() # 3. Commit (wait for 2f+1) if self.collect_commit_votes() >= 2self.f + 1: self.execute(request) ``` Tolerates f failures out of 3f+1 nodes. Related: Blockchain Consciousness (2050)