🤝 PBFT: Byzantine Fault Tolerance
Learn how networks reach consensus even with malicious nodes
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0 / 5 completed🛡️ What is PBFT?
Practical Byzantine Fault Tolerance (PBFT) is a consensus algorithm that enables distributed systems to reach agreement even when some nodes are faulty or malicious. It's the foundation of many enterprise blockchain platforms.
The Byzantine Generals Problem
The Original Problem (1982)
Byzantine generals surround an enemy city. They must all attack together to win, or all retreat to avoid defeat. Generals communicate via messengers, but messengers can be captured and some generals might be traitors.
Challenge: How can loyal generals reach consensus when communication is unreliable and traitors send conflicting messages?
🔍 Interactive: Problem Evolution
Explore how the Byzantine problem relates to blockchain consensus:
PBFT Solution
PBFT makes Byzantine consensus practical: fast, efficient, and provably secure with f < n/3 faulty nodes.
Scenario
Practical algorithm for Byzantine consensus
Challenge
Efficient with minimal message overhead
Solution
3-phase commit with voting
PBFT: Making It Practical
Fast
Reaches consensus in milliseconds, not minutes. 3-phase protocol with minimal overhead.
Secure
Mathematically proven to tolerate up to f < n/3 Byzantine (malicious) nodes.
Deterministic
No probabilistic finality. Once committed, transactions are final immediately.
Enterprise Ready
Perfect for permissioned blockchains where validators are known entities.
Key Innovation
PBFT was introduced in 1999 by Miguel Castro and Barbara Liskov. It made Byzantine fault tolerance practical for real systems by reducing message complexity from exponential to polynomial, enabling consensus with just 3 communication rounds.
Where PBFT is Used
Hyperledger Fabric
Enterprise BlockchainDefault consensus for private business networks
Zilliqa
Public BlockchainHybrid consensus combining PoW and PBFT
Tendermint
Consensus EnginePBFT-inspired consensus for Cosmos ecosystem
NEO
Smart Contract PlatformdBFT (delegated BFT) variant