A brief analysis of the Aptos public chain: What are the differences between the PayPal investment and the project created by Facebook members?

Author: Rhythm BlockBeats

Aiming to create a blockchain that can innovate quickly and adapt to the needs of billions of people today and in the future. Expecting significant improvements in user experience regarding security and scalability. Making the blockchain more applicable to ordinary users, especially non-crypto native users, to accelerate internet users' adoption of web3.

Team Background and Project Origin

Aptos was founded in 2021 and is headquartered in Palo Alto, California. The main leaders, Mo Shaikh and Avery Ching, were also key builders of Diem (formerly Libra) and Novi (formerly Calibra).

Meta (formerly Facebook) faced numerous challenges in the crypto space, leading to many projects being stalled and several members leaving Meta to continue their work in the crypto field. Mo Shaikh and Avery Ching were among them; after Diem was halted, they left Meta and gathered with many core developers, creators, researchers, and designers from Diem and Novi to establish a new network called Aptos based on the open-source Diem codebase.

Many current Aptos team members previously worked at Meta, which means the Aptos team has rich experience in large-scale development and deployment systems, and the Aptos team members are also familiar with the Move language, eliminating the need for new learning costs.

According to Aptos, co-founder Avery Ching is one of the world's leading experts in building distributed systems. Besides him, there are many other team members composed of PhDs, researchers, engineers, designers, and strategists, including Alden Hu, Alin Tomescu, Dahlia Malkhi, David Wolinsky, Greg Nazario, Jake Skinner, and Josh Lind.

Aptos is partially built on the technologies publicly developed by its team members over the past three years, planning to focus on security, scalability, and upgradability.

Security

Move Programming Language

In terms of language, Aptos uses the Move programming language, originally developed for Diem, which is designed for secure resource management and verifiable execution on the blockchain. Three years ago, these staff members were developing both the blockchain and the Move language. Currently, accounts, transaction fees, standard libraries, validator management, and configuration are all implemented through Move. Move is regarded by many as Diem's greatest innovation.

It is well-known that Ethereum's Solidity is one of the most commonly used languages among developers, powerful and well-scalable. Compared to it, Move stands out in terms of security, providing very strong security guarantees from the code level of underlying memory and smart contract programming.

Hotstuff Consensus Derivative

Aptos claims to have developed a production-grade, high-assurance, low-latency Byzantine Fault Tolerance (BFT) engine, implementing the fourth iteration of the consensus protocol (the state-of-the-art Hotstuff derivative) over the past three years. HotStuff is a leader-based Byzantine fault-tolerant replication protocol used for partially synchronous models. Once network communication becomes synchronous, HotStuff allows the correct leader to push the protocol to reach consensus at the actual network latency speed.

The Aptos team upgraded the consensus protocol in a private mainnet environment, adding an active pacemaker that uses timeouts to synchronize validators, far faster than waiting for increased timeouts, allowing blocks to be submitted with just two network round trips, achieving sub-second finality. Additionally, Aptos's reputation system can analyze on-chain states and automatically update leader rotations without any human intervention, applicable to unresponsive validators. The protocol clearly distinguishes between liveness and safety. Regardless of whether the network is unreachable or the non-safe core is compromised in some way, as long as the BFT honest guarantee is maintained, the chain will not fork.

Validation Testing, Keys, and Multi-Agent Transactions

To ensure security, the Aptos team runs a large number of validators in different environments and repeatedly tests Aptos Core.

Aptos has also set up account key recovery and rotation protocols to primarily prevent key theft, specifically allowing any account to rotate its private key, and validators can regularly rotate their consensus keys. To prevent key loss, Aptos is also developing new key recovery technologies that can be directly integrated into the blockchain account model.

Aptos allows for arbitrary numbers of atomic operations across multiple on-chain accounts in a single transaction through multi-agent transactions, utilizing Move's signer types.

Scalability

Metrics and Measurements

High transaction fees, low throughput, and high finality limit the popularity and development of blockchains. Aptos believes that L1 should focus on developing scalability to optimize user experience.

In terms of blockchain performance metrics, data may vary due to different testing benchmarks. Aptos intends to share benchmarking frameworks and compare performance characteristics of various use cases across different blockchains, such as throughput TPS (transactions per second) and finality (the time from when a client creates and submits a transaction to when the other party confirms that the transaction has been submitted).

Throughput and Finality

In planning to improve throughput and finality speed, Aptos plans to completely separate the consensus protocol from transaction execution. The team has begun developing the next iteration of the consensus protocol to promote transaction propagation, which may be launched on the testnet this year.

Additionally, another challenge is transaction execution time. Aptos uses new technologies inspired by software transactional memory, achieving over 130k transactions per second using only 32 cores in benchmark tests.

The final bottleneck in performance is the authenticated data structures and related state storage. When validating ledger states (e.g., account balances, smart contracts, etc.), in-memory Merkle trees are effective on a small scale but cannot write large Merkle trees to persistent storage. To address this issue, Aptos is designing authenticated data structures by exploring higher branching factors, cache optimizations for access patterns, and careful version control, and Aptos is also developing support for large accounts.

Parallel Account Transactions and Control of Transaction Ordering

Unlike the widely used serial number method in Ethereum, Aptos attempts to enhance the serial number method using anti-conflict serial numbers, allowing accounts to operate in parallel on the serial number window while still allowing users to control transaction ordering when necessary. Considering future implementations for more flexible and composable parallel account transactions.

Support for Different States of Management Nodes

In high-throughput blockchains, state synchronization between nodes can be CPU-intensive. Aptos supports a range of different state synchronization protocols. To support inexpensive full nodes, Aptos has a protocol that synchronizes transactions and their execution results signed by a quorum of validators, allowing nodes to skip computation at the cost of higher network throughput and directly update ledger state results from executed ledger states.

Unlike most blockchains that require downloading the blockchain to obtain the latest ledger, Aptos clients can use transaction accumulators to get the latest submitted transactions, and many previous transactions and ledgers can be pruned.

Upgradability

The development of blockchains is rapidly changing, from DeFi to NFTs to DAOs, with hot types constantly shifting. However, many underlying protocols struggle to make significant improvements after release, making it difficult for current networks to quickly adapt to the evolving web3 demands.

Aptos notes that some networks experienced downtime for hours when attempting significant upgrades, while others faced unexpected hard forks. Aptos manages validator management and configuration using on-chain states, facilitating community voting and rapid execution of upgrades, successfully executing multiple significant upgrades in the past few years without downtime, ensuring deployment is safe and reliable.

Funding Situation and Roadmap

On March 15, Aptos announced the completion of a $200 million funding round led by a16z, with participation from many well-known VCs such as Tiger Global, Katie Haun, Multicoin Capital, Three Arrows Capital, FTX Ventures, and Coinbase Ventures.

Subsequently, not only did Binance Labs announce an investment in Aptos Labs, but the payment giant PayPal also stated that it had participated in the investment, marking the first Layer 1 public chain project funded by PayPal Ventures. It is important to note that to maintain separation from Meta and ensure Aptos's independence, the project did not receive funding from Meta-related personnel.

According to the current roadmap of Aptos, the developer testnet will be launched in Q1 of this year, and developers can start building on the Aptos testnet from March 15. Collaborating with strategic partners and the web3 developer community while collecting feedback to improve the Move developer experience and the Move language.

In Q2, an incentivized testnet will be launched, providing a larger testing platform and collaborating with the node operator community to jointly operate a decentralized network. A bug bounty will be proposed to improve infrastructure and provide incentive mechanisms to protect network participants. It is worth noting that the difference between the development net and the test net is that the development net is primarily for trying out new ideas, while the test net is used to validate the results tested by core developers in preparation for the mainnet launch.

Aptos plans to launch the mainnet in Q3 of this year, with the next major version deployed to the Aptos mainnet from Q4 to Q1 of next year.

Currently, developers can build on the incentivized testnet, and the second phase of incentivized testing is about to begin, allowing users who meet the hardware requirements to run nodes and participate.

In terms of applications, Liquidswap, developed by Pontem, is the first decentralized exchange on the Aptos network. Pontem is a product development studio that claims it may also collaborate with Aptos to build development tools, EVM, AMM, and other DApps and infrastructure. In addition to Liquidswap, there is also the Fewcha wallet on Aptos. Moreover, Martian DAO is building various products for the Aptos ecosystem, including Martian Wallet and an NFT marketplace called Curiosity, which is worth paying attention to.