Understanding Solana: Architecture, Account Model, and Transactions - Part 1

Anatoly 2025-10-30 19:42 48369人围观 SOL

Understanding Solana: Architecture, Account Model, and Transactions - Part 1 Solana is a high-performance blockchain designed for speed, scalability, and low-latency transactions. Its architecture introduces several innovations that make it stand out from

Understanding Solana: Architecture, Account Model, and Transactions — Part 1

Solana is a high-performance blockchain designed for speed, scalability, and low-latency transactions. Its architecture introduces several innovations that make it stand out from traditional blockchains such as Ethereum and other EVM chains.

In this series, we will cover basic concepts that every developer or enthusiast should understand:

Core Architecture: How Solana achieves high throughput through proof-of-history, Tower BFT, and parallel transaction processing.

Account Model: Solana’s unique way of handling state and procedures through accounts.

Transactions: The structure, execution flow, and authorization model for Solana transactions.

In this article, we will start with the core architecture and cover the basics of solana before delving into the implementation.

core architecture

In this section, we'll provide a quick overview of Solana's core architecture and understand how it works.

Proof of History (PoH)

PoH is a key innovation of Solana, proposed by Anatoly Yakovenko, founder of Solana Labs. It is built on a simple but powerful idea: in a distributed system, knowing the precise sequence of events is as important as the events themselves.

To achieve this, Solana uses a Verifiable Delay Function (VDF), a cryptographic function that takes a measurable amount of time to compute and whose output can be efficiently verified. Each validator continuously hashes previous outputs as well as new data, resulting in a series of hashes that act as cryptographic timestamps of events. It provides a provable and immutable record of time, showing exactly when each event occurred relative to other events.

This design allows for fast finality, meaning that once a block is added to the blockchain, it is considered final and cannot be undone.

Verifiable Delay Function (VDF)

Traditional blockchains like Bitcoin and Ethereum rely on block intervals or external timestamps to order transactions, which limits scalability. Solana solves this problem by embedding time directly into the ledger using Verifiable Delay Functions (VDF).

VDF is a cryptographic function that takes a fixed amount of time to compute and can be verified quickly. The validator continuously runs this function, hashing the previous output to generate a chain of hashes, each hash representing a precise moment in time. This sequence creates a cryptographic clock that allows anyone to prove when an event occurred relative to other events without having to rely on external sources.

When transactions are submitted, they reference a specific point in this PoH sequence. Validators can immediately verify when they occur, enabling parallel verification and faster consensus. In the case of Solana, PoH works in conjunction with Tower BFT, a proof-of-stake based consensus mechanism that completes blocks in milliseconds.

The role of VDF in PoH addresses several key aspects of blockchain technology:

Verifiability: It ensures that the blockchain’s history is transparent, immutable, and verifiable by the public. This builds trust and reduces reliance on computationally intensive processes.
Decentralization: Multiple nodes can generate and verify timestamps simultaneously, preventing any single entity from controlling timestamp generation. This enhances the security and reliability of the network.
Efficiency: By providing a reliable chronological order of events without the need for energy-consuming consensus algorithms like Proof of Work (PoW), PoH with VDF improves transaction processing efficiency, accelerates consensus, and reduces transaction fees.

Tower BFT

Tower BFT is Solana’s consensus algorithm, built on Proof of Stake and tightly integrated with Proof of History. It is a customized version of Practical Byzantine Fault Tolerance (PBFT), optimized to take advantage of PoH's cryptographic clock. (We won’t cover the full process here, the full process can be read here)

In traditional PBFT systems, validators must constantly communicate to agree on the order of transactions, a process that limits scalability. Tower BFT reduces this communication overhead by using PoH as a trusted source of time. Since each validator can verify when an event occurs, they don't need to exchange as many messages to reach consensus.

Each validator votes on the state of the ledger and locks their votes into a certain number of "slots." Changing that vote later will require violating its own lock, so honest behavior is strongly encouraged. As validators continue to build on confirmed blocks, their lock duration increases exponentially, making finalization fast and irreversible.

Essentially, PoH provides a timeline and Tower BFT builds consensus on top of it, allowing Solana to complete blocks in milliseconds while maintaining security and decentralization.

how it works together

Encrypted timestamps: The core of PoH is encrypted timestamps, which uses a sequential hash function. This function takes an input (the current state of the blockchain and a random seed) and produces a unique, irreversible output (the hash). This hash acts as a verifiable timestamp.
Generating hash chains: Solana creates hash chains by iteratively applying a hash function to the output of previous hashes. Each step represents a timescale, and the number of hash operations represents the elapsed time. This produces a continuous, verifiable record of time used to sequence transactions.
Recording transactions: When a transaction is made, it is sent along with the latest hash observed. The validator confirms its validity and time by ensuring that it references the hash in the current PoH sequence. This proves that the transaction occurred at a specific moment.
Consensus: Once transactions are timestamped using Proof of History, they go through Solana’s Proof-of-Stake (PoS)-based consensus mechanism, called Tower BFT. Validators stake SOL to participate in the process, responsible for verifying transactions and maintaining network security in exchange for rewards. Thanks to PoH's built-in timing capabilities, Tower BFT can agree on the order of transactions very quickly, enabling Solana to process thousands of transactions per second.
Verifiable Delay Function (VDF): At the heart of proof of history lies VDF, a cryptographic process that enforces a measurable passage of time between events. Before generating a block, the leader must calculate the next hash in the sequence, which depends on the output of the previous hash. This ensures that each step can only be generated sequentially and cannot be skipped or parallelized. By continuously appending new hashes derived from previous states, Solana creates a verifiable chain of timestamps that proves the precise sequence of transactions, preventing anyone from recreating or reordering historical data.

Parallel transaction processing

In most blockchains (like Ethereum), transactions are processed sequentially, one after the other, because each transaction potentially modifies shared state (such as balances or contract data). This ensures consistency but limits throughput because the network can only handle as many transactions per second as a single thread can handle.

Solana takes a different approach with parallel transaction execution, powered by its runtime called Sealevel. Allowing Solana to achieve massive throughput, tens of thousands of transactions per second, without sacrificing determinism or consistency. (For more information on SeaLevel, see here)

In the next part, we'll take a deeper look at Solana's account model, how all state, programs, and data are organized in accounts, and how it differs from Ethereum's contract model.

Original link: https://medium.com/@andrey_obruchkov/understanding-solana-architecture-account-model-and-transactions-part-1-1bffae449650
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