Lightspeed Newsletter Segment

This is a segment from the Lightspeed newsletter. To read full editions, subscribe.

Imagine viewing the world financial system as a centralized deception that benefits a few at the expense of many. What if a fairer system could exist by decentralizing authority? Instead of a central entity validating transactions, independent participants could run their own nodes, using distributed consensus to verify and maintain the network.

The challenge is achieving agreement among thousands of decentralized actors, each motivated to cheat for profit. If even a small group deceives the network, confidence would collapse. Satoshi Nakamoto introduced proof-of-work (PoW), where miners hash block data with nonce values to find a solution that meets specific criteria. The first to succeed proposes a new block and earns bitcoin. No cheating occurs, as other nodes quickly verify or reject each block before it’s added.

This method has worked for Bitcoin (BTC), establishing it as a globally recognized, censorship-resistant store of value, albeit with trade-offs, leading to slow transaction speeds and high energy consumption. Bitcoin averages seven transactions per second (TPS), much lower than modern digital payment systems like Visa. Although layer-2 solutions like the Lightning Network enhance Bitcoin’s capacity, the base layer remains limited. Mining consumes energy comparable to entire nations, attracting scrutiny from environmentalists.

Fatal limitations have not hindered Bitcoin’s success, but Ethereum’s entry broadened scalability concerns. Smart contracts are more computationally intensive than simple transactions, with Ethereum’s base layer achieving only 15-30 TPS, leading to congestion, high fees, and slow confirmations during peak times.

Then came Solana’s breakthrough in 2017: proof-of-history (PoH).

PoH isn’t a consensus mechanism; it’s a cryptographic timekeeping system. Rather than continuously communicating to establish transaction order, PoH creates a verifiable sequence of events through continuous hashing (SHA-256), forming an immutable transaction timeline.

Key Takeaway: PoH theoretically allows Solana to validate 50,000 to 65,000 TPS, far exceeding Bitcoin and Ethereum’s capacities. With almost instantaneous transaction settlements, Solana ranks as one of the fastest public L1s. It combines PoH with proof-of-stake (PoS) to balance speed, security, and decentralization. Unlike traditional PoS networks, where validators must consistently agree on timestamps, Solana’s blockchain structure inherently encodes transaction order, allowing validators to focus solely on verification and security, bypassing a major consensus bottleneck.

Of course, PoH has its own downsides.