P2QRH / BIP-360 Update

The email from a peer in the Bitcoin Development community delves into a detailed analysis of potential blockchain scenarios aimed at enhancing transaction throughput and quantum resistance, with specific attention to the balance between chain growth rates and hardware requirements. The sender appreciates the recipient's calculations, which closely align with their own models, especially regarding the growth rates and implications for hardware.

Three primary scenarios are discussed, each offering different benefits and challenges based on their block sizes, transactions per block, transactions per second (TPS), and annual chain growth. The first scenario, QuBit16, features 10MB blocks with approximately 3,000 transactions per block, achieving around 5.6 TPS and leading to an annual chain growth of about 500GB. This scenario represents a balanced approach by providing moderate TPS and manageable chain growth. The second scenario, QuBit64, escalates the capacity with 17MB blocks and roughly 5,000 transactions per block, reaching about 8.3 TPS and a significant annual chain growth of around 900GB. Despite offering the highest TPS, this scenario poses hardware challenges due to its substantial chain growth. The third scenario, QuBitWit, does not include any attestation discount, resulting in smaller 3.5MB blocks with 1,000 transactions each, yielding a lower TPS of approximately 1.7 and a more modest annual chain growth of 185GB.

The analysis highlights the trade-offs between these scenarios. While the QuBit64 scenario provides throughput comparable to current Bitcoin capabilities enhanced by SegWit and Taproot, its nearly 1TB of annual chain growth could hinder decentralization by placing excessive demands on personal node operators. Conversely, the QuBit16 scenario is identified as a "sweet spot," offering satisfactory TPS and a storage growth rate that is more aligned with the capacities of current nodes.

Decentralization emerges as a critical consideration in this discussion. The consensus among exchanges and miners, who prioritize operational efficiency, may lean towards higher TPS solutions like QuBit64. However, from a decentralization standpoint, the QuBit16 scenario, with its lower storage demands, might be more appealing. Furthermore, the anticipated improvements in hardware, specifically the increased accessibility and affordability of 8TB+ NVMe drives, could mitigate concerns over high chain growth rates in the future.

The sender expresses interest in community feedback, particularly regarding preferences between maximizing TPS or maintaining lower storage requirements, and how these choices would affect decentralization efforts within the Bitcoin network.