[Short general description]: Solana is a new architecture for a high performance blockchain. It aims to support over 700 thousand transactions per second on a gigabit network.
[Main contribution proposal]: Solana proposes a new blockchain architecture based on Proof of History (PoH) - a proof for verifying order and passage of time between events. PoH is used to encode trustless passage of time into a ledger - an append only data structure. When used alongside a consensus algorithm such as Proof of Work (PoW) or Proof of Stake (PoS), PoH can reduce messaging overhead in a Byzantine Fault Tolerant replicated state machine, resulting inn sub-second finality times. At the same time, this project proposes two algorithms that leverage the time keeping properties of the PoH ledger - a PoS algorithm that can recover from partitions of any size and an efficient streaming Proof of Replication (PoRep). The combination of PoRep and PoH provides a defense against forgery of the ledger with respect to time (ordering) and storage. The protocol is analyzed on a 1 gbps network, and this paper shows that throughput up to 710k transactions per second is possible with todays hardware.
[Main problems tackled]:
Solving the agreement on time by using Proof of History. With Proof of History, you can create a historical record that proves that an event has occurred at a specific moment in time.The Proof of History is a high frequency Verifiable Delay Function. A Verifiable Delay Function requires a specific number of sequential steps to evaluate, yet produces a unique output that can be efficiently and publicly verified. Solana’s implementation uses a sequential pre-image resistant hash that runs over itself continuously with the previous output used as the next input. Periodically the count and the current output are recorded.
Inputs into Proof of History can have references back to Proof of History itself. The back reference could be inserted as part of a signed message with the users signature, so it cannot be modified without the users private key.
While the recorded sequence can only be generated on a single CPU core, the output can be verified in parallel.
1) Performant System Architecture - The network is arranged for maximum throughput and high availability. Solana’s smart contracts bytecode is based on Berkeley Packet Filter designed for fast execution.
2) Proof of History - Encoding time as data in the replicated state allows for simple and efficient proofs and protocols.
3) Fast Proof of Replication - A fast streaming Proof of Replication is designed for storing a large distributed ledger.
4) Consensus independent from transaction flow - Transactions flow through the network independent of consensus and are limited only by hardware.