Solana offers a new insight to blockchain architecture by combining a new mechanism known as Proof of History (PoH) with Proof of Stake (PoS) to achieve high availability throughout. PoH is a sequence of computations on a secure hash function that provides a way to cryptographically verify time elapsed between two events. The process involves taking the hash computed by an iteration of the hash function and reusing it as the input for another iteration, while also periodically recording the current output and how many times the hash function has been called. In addition to this, data can also be inserted into the sequence by appending the hash of the data to the previous state. Once appended, all other outputs are affected unpredictably, making the proof secure as it is impossible to generate desired hashes or create an alternative history given two identical hashes. To understand all of this, consider the following. A reader is confident that the events published in the New York Times actually occurred before the newspaper was written. This is proof that time has passed between two append operations and that the creation of data comes before it is appended to the PoH sequence. The input to the PoH sequence can also be a reference to some previously acknowledged PoH state.
While the PoH sequence can only be generated with a single CPU core, Solana allows parallelization of cores to assist in verification of the output. To give some perspective on this, a modern day GPU with 4000 cores can verify a second of PoH in 0.25 milliseconds. Solana’s underlying sequential design benefits from the aspect of horizontal scalability by synchronizing multiple PoH generators, and mixing their sequence states from each generator to each other generator. This scaling requires no sharding and ensures high probability of availability. Synchronizing the generators allows each generator to handle a portion of external traffic, thus the overall system can handle a larger amount of events to track. Furthermore, Solana utilizes PoS for voting, selecting the next PoH generator, and punishing misbehaving validators in the network. Solana’s Avalanche PoS system ensures efficient growth of the network with the increase of network connections per node.
Solana Strengths and Opportunities
The network will achieve low finality times even as the network expands, and smart contracts on the platform will feature very high performance. No project has been able to achieve such a massive level of throughput without resorting to other means of scaling. Solana’s testnet is live, performing at ~140,000 transactions per second. Solana’s Github has been updated consistently over the past few months.
Solana Weaknesses and Threats
A possibility of unfavorable incentives in the consensus protocol could lead to colluded 51% attacks. Moreover, there exist some threats the proof of replication model. Proofs can be generated at will which means the first block of every key rotation cannot be proved to be securely stored. As well, replicators can only store states temporarily.
Verdict on Solana
Solana introduces a novel way of modelling consensus with aspect to time that will achieve a very high throughput rate without sharding or off-chain scaling. Heavy performance-reliant infrastructures such as exchanges or distributed web services require such capacity. Solana will eliminate high markup, human capital costs, and more tradeoffs other consensus models make in pursuit of performance. The team is constantly delivering and seems devoted to me. I like the Solana project and the Solana token very much.
