The Economic Limits of Bitcoin and the Blockchain
The Economic Limits of Bitcoin and the Blockchain
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DOI：
10.2139/ssrn.3197300
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发表时间：
2018-06
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影响因子：
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通讯作者：
Eric Budish
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作者：
Eric Budish
投入到匿名、去中心化区块链(如比特币的区块链)上的计算能力必须同时满足两个均衡条件：(1)矿工之间的零利润条件，他们参与了与向链中添加下一个区块相关的奖金的寻租竞争；以及(2)关于系统易受“多数攻击”攻击的激励兼容性条件，即此类攻击的计算成本必须超过收益。这两个等式加在一起意味着：(3)与攻击区块链的一次性“股票”收益相比，为运行区块链而向矿工支付的经常性“流量”肯定很大。这太贵了！如果(I)用于运行区块链的挖掘技术既稀缺又不可重复使用，以及(Ii)任何多数攻击都是一种“破坏”，因为它会导致区块链的经济价值崩溃，则约束更为温和(即，股票与股票)；然而，对安全的不可重复使用技术的依赖和对破坏的脆弱性各自提出了各自的担忧，并指出了具体的崩溃场景。特别是，该模型表明，如果比特币在经济上变得足够重要--例如，如果它成为一种类似黄金的“价值储存”--比特币将受到多数人的攻击，这表明，比特币在经济上的重要性首先会受到内在的经济限制。
The amount of computational power devoted to anonymous, decentralized blockchains such as Bitcoin's must simultaneously satisfy two conditions in equilibrium: (1) a zero-profit condition among miners, who engage in a rent-seeking competition for the prize associated with adding the next block to the chain; and (2) an incentive compatibility condition on the system's vulnerability to a “majority attack”, namely that the computational costs of such an attack must exceed the benefits. Together, these two equations imply that (3) the recurring, “flow”, payments to miners for running the blockchain must be large relative to the one-off, “stock”, benefits of attacking it. This is very expensive! The constraint is softer (i.e., stock versus stock) if both (i) the mining technology used to run the blockchain is both scarce and non-repurposable, and (ii) any majority attack is a “sabotage” in that it causes a collapse in the economic value of the blockchain; however, reliance on non-repurposable technology for security and vulnerability to sabotage each raise their own concerns, and point to specific collapse scenarios. In particular, the model suggests that Bitcoin would be majority attacked if it became sufficiently economically important — e.g., if it became a “store of value” akin to gold — which suggests that there are intrinsic economic limits to how economically important it can become in the first place.