Aptos Blockchain was created with scalability, safety, stability, and upgradeability as its guiding principles. Over 350+ engineers from across the world have worked on the Aptos blockchain over the past three years.

In this blog post, we will understand everything about Aptos (APT) blockchain from its working, and use cases to its token economics.

Let’s get started!

What is Aptos (APT)?

Aptos is a Layer 1 Proof-of-Stake blockchain that uses a unique smart contract language called Move. Developed by the engineers behind the Diem blockchain (formerly known as Facebook’s blockchain project), Move is a programming language based on Rust.

Aptos aims to bring mainstream adoption to web3 and enable an ecosystem of DApps to address practical user issues.

The PoS blockchain is capable of theoretically processing over 150,000 transactions per second through parallel execution.

How does Aptos Blockchain Work?

The Aptos blockchain utilizes various protocols to ensure security, reliability, and scalability. According to Aptos, its testnet is currently able to process nearly 130,000 transactions per second. Some of the features of the Aptos blockchain include:

1. First, it natively integrates and uses the Move language for fast and secure transaction execution, with the Move Prover offering additional protection for smart contract invariants and behavior.
2. Second, the Aptos data model allows for flexible key management and hybrid custodial options, as well as transparent transactions before signing and practical light client protocols, providing a safer and more trustworthy user experience.
3. Third, the Aptos blockchain employs a pipelined and modular approach for transaction processing, with transaction dissemination, block metadata ordering, parallel transaction execution, batch storage, and ledger certification all occurring concurrently, allowing for high throughput and low latency and fully leveraging available resources.
4. Fourth, unlike other parallel execution engines that require upfront knowledge of data to be read and written, the Aptos blockchain can efficiently support atomicity with complex transactions, enabling higher throughput and lower latency for real-world applications and simplifying development.
5. Fifth, the Aptos modular architecture design supports client flexibility and allows for frequent and instant upgrades, with on-chain change management protocols for rapid deployment of new technology innovations and support for new web3 use cases.

Founders and Developers

Aptos was founded by Mo Shaikh and Avery Ching, both former employees of Meta. Shaikh, the current CEO of Aptos, has a background in financial services and blockchain/cryptocurrency and has experience in scaling products and the private equity and venture capital markets.

Ching, the CTO of Aptos, is a software engineer who previously served as a principal software engineer at Meta.

Both Shaikh and Ching worked on the Diem blockchain project at Meta before forming Aptos Labs when the Diem project was discontinued in January 2022.

It is not surprising that Aptos incorporates some elements of Diem, as the team includes researchers, designers, and engineers from the Diem project.

Pros and Cons of Aptos Blockchain

Key Components of Aptos Blockchain

According to Aptos Whitepaper, In order to provide secure, fast, reliable, and upgradeable web3 infrastructure for widespread adoption, the Aptos blockchain is based on the following core design principles:

• Fast and secure execution, as well as simple auditability and mechanical analyzability, through the use of the Move smart contract programming language. The move was developed for the Aptos blockchain and continues to evolve with the project.
• Extremely high throughput and low latency through a batched, pipelined, and parallelized approach to transaction processing.
• A novel parallel transaction processing method that efficiently supports atomicity with complex transactions through Block-STM, unlike other parallel execution engines that require prior knowledge of data locations.
• Optimizations for performance and decentralization through rapid, stake-weight validator set rotation and reputation tracking.
• Upgradeability and configurability as key design considerations to accommodate new use cases and emerging technology.
• Modular designs that allow for thorough component-level testing, threat modeling, and seamless deployment to ensure secure and reliable operations.
• Horizontal throughput scalability while preserving decentralization, with sharding being a native concept for users and the programming and data model.

What is Move Programming Language?

Move is a smart contract programming language designed with a focus on safety and flexibility. It is used on the Aptos blockchain to represent the ledger state and encode rules for state transitions.

Transactions can be submitted to create new modules, update existing ones, execute specific functions within a module, or include scripts that interact directly with the public interfaces of modules.

The Move ecosystem includes a compiler, a virtual machine, and other tools for developers. It is based on the Rust programming language and emphasizes resource conservation, preservation, and access control.

Move modules define the lifetime, storage, and access pattern for every resource, ensuring that resources like Coin cannot be produced or spent improperly and do not disappear.

Move employs bytecode verification to ensure type and memory safety with untrusted code, and it includes a formal verifier called the Move Prover that can confirm the functional correctness of a program against a given specification.

Move’s support for module upgradeability and comprehensive programmability enables smooth configuration changes and supports upgrades to the Aptos blockchain itself (both types of upgrades have been successfully implemented with no downtime on a private mainnet).

The Aptos team has further enhanced Move to support a wider range of web3 use cases. The Aptos blockchain allows for fine-grained resource control, which not only enables parallel execution but also has a nearly fixed cost for accessing and modifying data.

It also includes table support built on top of fine-grained storage, enabling large datasets (such as collections of NFTs) to be stored in a single account.

Aptos also supports shared or autonomous accounts that are represented entirely on-chain, allowing complex decentralized autonomous organizations (DAOs) to collaboratively share accounts or use them as containers for diverse resources.

Aptos Logical Data Model

The Aptos blockchain’s ledger state represents the status of all accounts. It is versioned using an unsigned 64-bit integer that corresponds to the number of transactions that have been executed on the system. Anyone can submit a transaction to modify the ledger state.

When a transaction is executed, it generates a transaction output that includes zero or more operations to manipulate the ledger state (called write sets), a vector of resulting events, the amount of gas consumed, and the transaction’s status.

A signed transaction includes:

• Transaction authenticator: The sender uses one or more digital signatures to verify the authenticity of the transaction.
• Sender address: The account address of the sender.
• Payload: The payload either refers to an existing on-chain entry function or contains an inlined bytecode function (called a script) to be executed, along with a set of input arguments encoded in byte arrays. For a peer-to-peer transaction, the inputs include the recipient’s information and the amount being transferred.
• Gas price (in specified currency/gas units): The amount the sender is willing to pay per unit of gas to execute the transaction. Gas is used to pay for computing, networking, and storage, with a gas unit being an abstract measure of computation with no inherent value.
• Maximum gas amount: The maximum gas units the transaction is allowed to consume before it is aborted. The sender’s account must have at least the gas price multiplied by the maximum gas amount, or the transaction will be discarded during validation.
• Sequence number: The transaction’s sequence number, which must match the sequence number stored in the sender’s account when the transaction executes. Upon successful execution, the account’s sequence number is incremented to prevent replay attacks.
• Expiration time: A timestamp after which the transaction becomes invalid.
• Chain id: Identifies the blockchain that the transaction is valid for, providing additional protection against signing errors.

What is Move Ledger State?

From the perspective of the Move virtual machine, each account in the Aptos blockchain consists of a set of values and key-value data structures called table entries, which are stored in the Binary Canonical Serialization format.

This allows developers to write smart contracts that can efficiently handle small amounts of data replicated across many accounts or large amounts of data stored in a few accounts. Move modules are stored in a similar way to account data but under a separate namespace.

The initial set of accounts and their associated state at the start of the blockchain is defined in the genesis ledger state.

At its launch, the Aptos blockchain will have a single ledger state, but as adoption grows and technology advances, it will scale up the number of shards to increase throughput and support transactions that move or access assets across shards.

Each ledger state will maintain all on-chain assets for its specific shard and provide the same account model with a fine-grained, key-value data store that has nearly fixed costs for storage access.

Pipelining, batching, and parallel transaction processing

To improve throughput, concurrency, and ease of development, the Aptos blockchain divides transaction processing into separate stages that are independent and individually parallelizable, similar to modern superscalar processor architectures.

This not only enhances performance but also enables new modes of interaction between validators and clients. For example:

• Clients can be notified when specific transactions have been included in a batch of persisted transactions, which are likely to be committed soon.
• Clients can be informed when a batch of persisted transactions has been ordered, allowing them to execute transactions locally and reducing latency in determining the output of executed transactions.
• Clients can choose to wait for certified transaction execution by validators and perform state synchronization based on the attested results.

The modular design of Aptos helps to speed up development and enables faster release cycles, as changes can be targeted at individual modules rather than the entire architecture.

It also allows for scaling validators beyond a single machine, providing access to additional compute, network, and storage resources.

What is Homogeneous state sharding in Aptos Blockchain?

Homogeneous state sharding allows for horizontal scalability in terms of throughput and enables developers to use a single universal state across shards. It also makes it easy for wallets to incorporate sharded data for their users.

This approach offers both performance benefits and the simplicity of a single, unified Move smart contract platform.

Initially, the Aptos blockchain will have a single ledger state. However, the network plans to achieve horizontal scalability while maintaining decentralization through the use of multiple sharded ledger states, each with a consistent API and sharding as a primary concept.

The Aptos token will be used for transaction fees, staking, and governance on all shards. Users and developers can transfer data between shards using a consistent bridge and can select their own sharding schemes based on their needs.

How Is the Aptos Network Secured?

Proof-of-Stake and AptosBFT are the two consensus protocols used by Aptos. DiemBFT, which was first created for the Diem blockchain, is comparable to AptosBFT.

Byzantine Fault Tolerant, or “BFT,” refers to a network’s ability to function even if some of its users are hostile or go offline. A unique consensus algorithm built on the HotStuff protocol is called AptosBFT.

The protocol secures the network through a series of intricate technical aspects, but without the need for user intervention, the algorithm evaluates the on-chain status and automatically changes leader rotations to account for non-responsive validators.

Aptos (APT) Token Economics

Mainnet was launched on October 12, 2022. The initial total supply of Aptos tokens (APT) at mainnet was 1 billion tokens. APT will have 8 digits of precision as part of the fraction where the minimal unit is called an Octa.

APT is the native cryptocurrency of the Aptos blockchain. It has a total initial supply of 1 billion, with a circulating supply of 130 million APT at the time of writing.

The distribution of APT is as follows: Community (51.02%), Core Contributors (19.00%), Foundation (16.50%), and Investors (13.48%).

The Community allocation includes approximately 80% held by the Aptos Foundation and the rest held by Aptos Labs. This portion will be used to support community growth and Aptos Foundation initiatives, with the remainder to be unlocked monthly over the next 10 years.

Investors and core contributors are subject to a four-year vesting schedule from the mainnet launch. The Aptos team announced an airdrop of 20 million APT tokens to early testnet users on October 19, 2022.

References

1. https://aptos.dev/assets/files/Aptos-Whitepaper-47099b4b907b432f81fc0effd34f3b6a.pdf
2. https://aptosfoundation.org/currents/aptos-tokenomics-overview
3. https://github.com/aptos-labs/aptos-core
4. https://github.com/move-language/move
5. https://developers.diem.com/papers/diem-move-a-language-with-programmable-resources/2019-06-18.pdf