谁制定加密货币的区块奖励、哈希难度等全局规则？区块奖励能否篡改？

Great questions—these are exactly the kind of core mechanics that trip up even folks who’ve dug into crypto lectures, so you’re in good company! Let’s break this down clearly:

1. Who sets the "global rules" for Bitcoin (block rewards, hash requirements, block size, etc.)? #

Bitcoin is a decentralized protocol, which means there’s no single authority (like a bank or government) calling the shots. Here’s how the rules work:

• The foundational rules were written into the original Bitcoin code by Satoshi Nakamoto back in 2009.
• Over time, changes to the rules are proposed via Bitcoin Improvement Proposals (BIPs)—these are formal documents drafted by developers, miners, and community members that outline proposed updates.
• For a rule change to become "global," it needs consensus across the network: the vast majority of node operators (people running Bitcoin software) and miners must adopt the updated code. If enough parties refuse to upgrade, the network splits into two separate blockchains (a "fork")—each following its own set of rules.
• Examples: The 2017 SegWit upgrade (which changed how transaction data is stored) and debates over block size limits were all decided through this community consensus process. No single person or group can unilaterally change the rules and have the rest of the network follow.

2. Who decides the block reward amount? Can it be tampered with? #

Let’s unpack this step by step:

• The block reward amount is hard-coded into the Bitcoin protocol with a fixed, pre-determined schedule. The rule is straightforward: every 210,000 blocks (roughly every 4 years), the block reward is halved. Starting at 50 BTC per block, it dropped to 25 BTC, then 12.5 BTC, then 6.25 BTC, and most recently to 3.125 BTC in 2024.
• Your local Bitcoin software follows this protocol rule, but it’s not just a local setting. If a miner tried to tamper with their software to claim a higher reward (say, 20 BTC instead of 12.5), the rest of the network would reject their block. Every node on the network validates incoming blocks against the protocol rules—if a block doesn’t meet the requirements (including the correct reward amount), it gets discarded immediately.
• Miners don’t need to "ask" other clients about the current reward amount because the schedule is universal. All compliant nodes use the same logic to calculate the reward based on how many blocks have been mined. Tampering with this logic on your own node just means your blocks won’t be accepted by the rest of the network, so you won’t actually earn any valid Bitcoin from them.

Content sourced from Stack Exchange, question author: Hatefiend