Definition
Proof of History (PoH) is a cryptographic time-ordering mechanism used in certain blockchains to create a verifiable sequence of events. It relies on a continuously computed, verifiable delay function whose outputs serve as timestamps, allowing network participants to confirm the order and relative timing of transactions and messages without relying on traditional synchronized clocks or external time sources.
In Simple Terms
Proof of History is a way for a blockchain to keep a built-in, tamper-evident timeline of events. It uses cryptographic calculations to produce a chain of timestamps, so the network can agree on when each transaction happened and in what order, without depending on outside clocks or separate time services.
Context and Usage
Proof of History is discussed as a core consensus-supporting mechanism in high-throughput blockchain designs, particularly in systems focused on parallel transaction processing and low-latency block production. It is referenced when analyzing how a network orders transactions, coordinates validators, and structures blocks in relation to its main consensus algorithm, especially in architectures that combine PoH with other consensus mechanisms.