Capacity Analysis of Public Blockchain
This provides a quantitative analysis of blockchain capacity and consistency trade-offs, addressing a gap in existing qualitative studies, which is important for blockchain developers and researchers in distributed systems.
The paper tackles the problem of quantifying the capacity of Proof-of-Work public blockchains in non-ideal networks, deriving a closed-form expression for capacity in the two-miner case and extending the model to analyze robustness against double-spending attacks, with validation showing accurate results.
As distributed ledgers, blockchains run consensus protocols which trade capacity for consistency, especially in non-ideal networks with incomplete connectivity and erroneous links. Existing studies on the tradeoff between capacity and consistency are only qualitative or rely on specific assumptions. This paper presents discrete-time Markov chain models to quantify the capacity of Proof-of-Work based public blockchains in non-ideal networks. The comprehensive model is collapsed to be ergodic under the eventual consistency of blockchains, achieving tractability and efficient evaluations of blockchain capacity. A closed-form expression for the capacity is derived in the case of two miners. Another important aspect is that we extend the ergodic model to analyze the capacity under strong consistency, evaluating the robustness of blockchains against double-spending attacks. Validated by simulations, the proposed models are accurate and reveal the effect of link quality and the distribution of mining rates on blockchain capacity and the ratio of stale blocks.