🏆 The Longest Chain Wins
Understand how the network automatically picks the valid chain
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0 / 5 completed⚖️ How Forks Get Resolved
When multiple chains compete, the network needs clear rules to decide which one wins. Let's explore the mechanisms blockchains use to achieve consensus!
🎯 The Resolution Challenge
In a decentralized network, there's no central authority to declare "this chain is correct." Instead, nodes follow predetermined rules to independently reach the same conclusion.
🎮 Chain Race Simulator
Watch two competing chains race to become the longest. Chain A has 60% mining power, Chain B has 40%:
Even with less hash power, Chain B sometimes wins temporarily. But over time, Chain A's advantage compounds. This is why 51% attacks require sustained majority control!
🔧 Resolution Mechanisms
Different blockchains use different strategies to resolve forks:
Most Proof-of-Work blockchains (Bitcoin, Ethereum pre-merge)
Casper FFG (Ethereum), Tendermint (Cosmos)
Periodic finalization points
Ethereum (pre-merge), considers uncle blocks
⚔️ 51% Attack Scenario
What if an attacker controls majority hash power? They can create a longer private chain and reorganize the network!
Attacker mines blocks secretly with majority hash power, creating longer chain
Send transaction on public chain (e.g., exchange deposit), wait for confirmations
Exchange credits account, attacker withdraws different cryptocurrency
Broadcast private chain - it's longer, so network reorganizes. Original transaction disappears!
Bitcoin: ~$15 billion in hardware + electricity. Ethereum PoS: Must stake 51% of all ETH (~$100+ billion).
Wait for deep confirmations (6+ blocks). Monitor for unusual network activity. Use finality gadgets (PoS).
📊 Resolution Time Comparison
💡 Key Insights
Fast finality requires validator voting (less decentralized). Longest chain is simpler but slower to finalize.
Resolution mechanism must make attacks more expensive than potential gains. Both PoW and PoS achieve this differently.
Resolution speed depends on network latency, node connectivity, and mining/validator distribution.