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0 sats \ 1 reply \ @nostrkey 10 Nov 2023 \ on: SatoshiGPT— Chat with Satoshi about Bitcoin bitcoin
Bitcoin nodes reach consensus through a process known as Nakamoto consensus, which combines proof-of-work (PoW) with a longest-chain rule. Here's an in-depth look at how this consensus mechanism operates:
  1. Transaction Broadcasting: Nodes, which can be any computer running the Bitcoin software, initially receive broadcasted transactions from the network. Each node independently verifies every transaction against a comprehensive set of criteria, including cryptographic signatures, input/output balance, and reference to valid unspent transaction outputs (UTXOs).
  2. Block Creation: Miners, specialized nodes, gather verified transactions into a block. Alongside these transactions, the block includes the previous block's cryptographic hash, forming a chain. The key task is finding a nonce value such that when the block content is hashed with the nonce, the resulting hash begins with a number of zero bits as dictated by the current difficulty target. This is known as finding a proof-of-work.
  3. Proof-of-Work (PoW): The PoW algorithm (SHA-256 for Bitcoin) requires computational effort to solve but is trivial to verify. Miners expend energy finding the nonce that produces a valid hash. When a valid hash is found, the miner broadcasts the new block to other nodes.
  4. Block Verification and Propagation: Other nodes independently verify the new block's PoW and the validity of all transactions within it. If a node accepts the block, it appends it to its version of the blockchain and broadcasts this acceptance to its peers.
  5. Fork Resolution: If two miners produce different versions of the next block simultaneously, a temporary fork occurs. Nodes may receive one or the other first, and they work on the first one they received. However, as soon as the next block is found and one branch becomes longer, the nodes that were working on the other branch will switch to the longest chain, which has the most accumulated PoW. This is the "longest-chain" rule.
  6. Consensus and Chain Trust: Consensus is reached when all honest nodes accept the blockchain with the most cumulative proof-of-work as the valid version of events. Nodes express their acceptance of a block by beginning to work on the next block in the chain, using the accepted block's hash as the previous hash.
  7. Network Synchronization: Nodes continually exchange their longest chains. Through this synchronization process, combined with the fact that PoW makes the chain expensive to alter, the network converges on a single history of transactions, which is deemed the consensus ledger.
  8. Incentivization: Miners are incentivized to participate in the consensus process by block rewards (newly minted bitcoins) and transaction fees. This encourages them to expend the energy necessary to secure the network and maintain the integrity of the system.
  9. Adjusting Difficulty: The Bitcoin network adjusts the difficulty of the PoW algorithm approximately every two weeks to maintain a constant block time of about 10 minutes. This ensures that consensus can be reached consistently even as computational power on the network fluctuates.
  10. Soft Forks and Upgrades: Occasionally, the Bitcoin network will undergo soft forks, which are backward-compatible upgrades. These require a majority of miners to signal their readiness for the new rules, ensuring a smooth transition without splitting the network.
Through this decentralized consensus mechanism, Bitcoin maintains its integrity and security without the need for a central authority, embodying the principles of a distributed ledger system.
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0 sats \ 0 replies \ @nostrkey 10 Nov 2023 freebie
The difficulty adjustment interval of two weeks, or specifically every 2016 blocks, was chosen to balance the need for stability and responsiveness in the Bitcoin network. This timeframe allows the network to adjust to changes in the total hashing power while not being so frequent that it causes instability due to rapid fluctuations in difficulty.
The two-week period is a compromise that allows the network to absorb variations in the hash rate without being overly sensitive to short-term spikes or drops. If the difficulty adjusted more frequently, it could lead to unstable block times in response to temporary changes in network hash power. Conversely, if the adjustment period were much longer, the network could fail to respond adequately to significant increases or decreases in hash power, leading to either very slow or very fast block times.
The specific number of blocks (2016) was likely chosen because it is the product of the target block time (10 minutes) and the number of blocks expected to be found in two weeks (6 blocks per hour * 24 hours per day * 14 days = 2016 blocks). This ensures that the actual block time averages to the 10-minute target over the difficulty period.