We present Prism [1], a new consensus protocol which retains the security guarantee of Bitcoin against an adversary with 49% hashing power while provably scaling the transaction throughput to network capacity and achieving a confirmation latency near the network delay. Prism is a natural generalization of the longest chain protocol but overcomes its security-scalability tradeoff by decoupling the proposing, voting and transaction processing functionalities of the blockchain. An implementation in Rust [2] achieves a throughput of 70,000 transactions per second and a confirmation latency of tens of seconds at 10^{-9} reversal probability on networks of up to 1000 EC2 Virtual Machines. 

[1] V. Bagaria et al, "Prism: Deconstructing the Block to Approach Physical Limits", arXiv:1810.08092, to appear ACM Computer and Communications Security Conference, 2019.

[2] L. Yang et al, "Prism: Scaling Bitcoin by 10,000 X",  arXiv:1909.11261.

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