Solana is a blockchain protocol built on top of a cryptographically secure, trustless time source that can decouple transaction processing and consensus operations.
Solana is a high-throughput blockchain reportedly capable of handling 710,000 transactions per second, rivaling such centralized systems as Visa, Google, and even NASDAQ. The blockchain does not rely on shards, partitions, side chains, multi chains, or any other feature that may negatively impact network security. Rather, one node processes transactions into a single stream of events secured on an append-only ledger and distributes subsets of the ledger throughout the network, greatly reducing the impact of latency and validation.
Solana’s CEO, Anatoly Yakovenko, led the development of operating systems at Qualcomm, distributed systems at Mesosphere, and compression at Dropbox. He holds two patents for high performance operating systems protocols and was a core kernel developer for BREW. The remainder of Solana’s dev team also comes from Qualcomm, specializing primarily in embedded systems, data science and GPU optimization.
Solana secures transactions on the blockchain and defends against ledger forgery using a combination of Proof-of-History (PoH), Proof-of-Stake (PoS), and Proof-of-Replication (PoRep). A pyramid-like network data flow schema, dubbed ‘Avalanche’, contributes to the protocol’s potential for high transaction throughput by splitting the bandwidth between downstream nodes and sending each only a portion of transmitted packet data. Sending only a portion of the data to each validator in the first layer in lieu of transmitting the packet to each node in its entirety allows for materially increased efficiency. As a result, finality times scale as a logarithmic function of the total number of network nodes, rather than scale along the more common linear function, drastically reducing network throughput as network nodes are added to the system.
Proof-of-Time is a way to cryptographically verify the passage of time between two events. Solana appends transactions to its ledger in the context of a sequence of computations known as a SHA-256 hash chain. Although it is difficult to confirm precisely how much time has elapsed between transactions, since the hash function is collision resistant, it is computationally impossible to pre-compute any future sequences based on prior knowledge of the data that will be integrated into the sequence. This allows an observing node to determine which events were appended to the ledger after other events, thereby establishing relative event order. Conceptually, this amounts to creating one-transaction blocks; though, in Solana, blocks are created very rapidly. It is worth clarifying that Solana does not necessarily establish which events actually occurred off-chain before other events but rather clarifies which events were appended to the ledger after other events—something that is not readily apparent in blockchain systems that package transactions into blocks.
The system architecture features two types of actors, PoH Leaders and Validators (sometimes referred to as Verifiers.) PoH Leaders are periodically elected by Validators.
Leaders: A Validator elected PoH Generator, or ‘Leader’, receives user transactions and outputs a PoH sequence that guarantees a specific global order. After each batch of transactions, the Leader outputs a signed signature of the state that is the result of processing the transactions in that order. The Leader then sends its recommended state to Validators down the pyramid to some constant number of Validators, each of whom then passes the pieces they received both to the Validators on their level and to a number of lower level Validators. As a result, there are only a relatively small and constant number of connections at each level of the pyramid.
PoS is used in this process to quickly confirm the current sequence produced by the PoH generator, for voting and selection of the next PoH generator, and as oversight for misbehaving Validators— PoH Generators are responsible for keeping Validators from blindly approving batches by periodically intentionally sending invalid hashes.
Validator: Besides participating in consensus, Validator nodes oversee and select Leaders and replicate the blockchain state. Solano’s storage protocol uses Proof of Replication (PoRep) to increase availability by making it unnecessary for all network nodes to store the full ledger. The mechanism, comparable to Filecoin’s, ensures that each piece of data has been replicated to its own unique dedicated physical storage node, allowing the network to prove that an untrusted node is using its resources to store a specific piece of the ledger. The result is a torrent-like network where no single node holds the complete ledger, but a copy is always available.
Sols (SOL) are Solana’s native, fungible, freely-tradable cryptoasset. Sols’ main function within the Solana network is compensation for transaction processing by nodes. Fractional sols are referred to as ‘lamports,’ which are equal to approximately 0.0000000000582 sols (comparable to BTC’s ‘satoshis’). Solana has held three token sale events: a 2018 SAFT raising $8,750,000, a 2019 ICO raising $20,000,000, and a 2020 IEO raising $2,400,000. Sols have a fixed supply cap of 500,000,000 tokens.