Blockchain: Mining, Consensus & Chain Validation Simulator

Blockchains chain data together through hashes: each block stores the hash of the block before it, so a chain of blocks becomes self-verifying — anyone can recompute every hash and confirm nothing was altered. This simulator builds that chain in real time. Click "Mine next block" to append a block, watching a simulated Proof-of-Work nonce search or a Proof-of-Stake validator selection play out depending on the chosen consensus mode, with mining difficulty controlling how much work a Proof-of-Work hash requires. Click "Tamper with a past block" to edit an already-confirmed block's data and see its hash change live — breaking the link to every block that came after it, exactly the immutability guarantee that makes rewriting blockchain history so expensive in practice.