02 Arbitrum ONE & NOVA – Why Arbitrum is L2 No.1

This series of posts is content created in collaboration with the Aslan Academy research team, ART: Aslan Research Team, affiliated with the blockchain research society Aslan Academy.

This series of posts has been prepared to help understand Arbitrum, following the support of Arbitrum by Luniverse NOVA.

In the previous post, we briefly looked at Arbitrum and its products. In this post, we will delve into the technical details of Arbitrum ONE and NOVA, and compare them with Optimism.

Arbitrum vs Optimism

Arbitrum ONE is an Ethereum Layer 2 scaling solution based on Optimistic Rollup (ORU). It was introduced in 2021 and is the first EVM rollup technology to achieve the second stage of decentralization. EVM rollup is a technology for improving Ethereum’s scalability by bundling multiple transactions into one and processing them on Ethereum’s L1 chain, reducing gas costs.

Validity Proof vs Fraud Proof

Rollups are divided into two types: Validity Proof and Fraud Proof.

Validity Proof provides a calculation formula that proves the correctness of the state change when transferring transaction data processed on Layer 2 to Layer 1. Through this formula, Ethereum L1 can immediately verify the validity of the submitted data and reflect it on the main chain. It is important to note that the type of Layer 2 solution varies depending on the verification method and technology used. Zero-knowledge Rollup (ZK Rollup) is a L2 solution that uses zero-knowledge proofs to prove the validity of all transactions without assuming any transaction.

Fraud Proof assumes that the transaction data processed on Layer 2 is correct and only verifies it if someone challenges it, submitting it to Ethereum L1. This reduces transaction verification costs.

However, in the case of Fraud Proof, a dispute period of 7 days is usually provided in case the sequencer engages in malicious behavior. During this period, the submitted results from the sequencer are not final, and a fraud proof process takes place between the sequencer and the challenger if challenged. If it is determined that the sequencer engaged in malicious behavior, the sequencer is penalized and the challenger is rewarded. This fraud proof process can only take place for a week, and after the period is over, the transaction data cannot be changed and is finally approved. The most representative Layer 2 solution that adopts this fraud proof method is Optimistic Rollup.

Optimistic Rollup is an effective technology for improving Ethereum’s scalability and reducing transaction costs. However, due to the nature of Fraud Proof, there is a possibility that the sequencer may engage in malicious behavior. To prevent this, it provides rewards and penalties for the sequencer, and security measures such as setting a dispute period.

Optimistic Rollup and ZK Rollup are both technologies for improving Ethereum’s scalability. In addition to the verification method and dispute period, they also differ greatly in EVM compatibility.

ZK Rollup does not have a dispute period and is immediately verified, but currently there are no ZK Rollups that provide EVM compatibility, making development difficult.

Actual TVL occupancy rate

Although Optimistic Rollup and ZK Rollup have their own advantages and disadvantages, they currently (as of 08.10) occupy about 85% of TVL L2. It can be evaluated that the market still shows more trust in Optimistic Rollup than in ZK Rollup.

Interactive Fraud Proof vs Non-Interactive Fraud Proof

There are two main types of Fraud Proof.

Non-interactive fraud proofs

Interactive fraud proofs

Non-interactive fraud proofs do not require the participation of an external party in the proof process of the accuracy of the claim. This method explicitly shows how the claim has changed between two claims by executing all state changes between the two claims on the chain.

The main advantage is that its design and interpretation are very simple. However, without using zk-proofs, the changes between two claims are limited to what can be processed on the chain. Considering the current performance of Ethereum, this style of fraud proof is limited in its ability to process effectively.

In the case of Interactive fraud proofs, two or more parties collaborate to determine the validity of the claim. This process involves a defender who raises the claim and a challenger who challenges it. The challenger only verifies the claim if someone challenges it. The most representative Layer 2 solution that adopts this fraud proof method is Optimistic Rollup.


Single-round Interactive Proof vs Multi-round Interactive Proof

The Single-round Interactive Proof method involves directly re-executing the challenged transactions on Ethereum’s L1 to determine whether the challenge is valid, based on the calculated state root, for validating the validity of a roll-up transaction. This method can easily detect fraud, but it has the disadvantage of relatively high gas costs and an increase in on-chain data.

The Multi-round Interactive Proof method involves dividing the challenged transaction into multiple stages for analysis. The roll-up transaction in question is divided into two equal parts, and the challenger chooses which part to challenge. The selected part is further divided, and this process is repeated until only claims for a single execution step remain. In the last stage, the L1 contract evaluates this execution step to confirm the party responsible for committing fraud. This method is efficient because it minimizes the work of the L1 chain in dispute resolution, making it an advantage over the Single-round Interactive Proof method.

Fraud Proof of Arbitrum

Arbitrum belongs to the category of Interactive fraud proofs among the two types of fraud proofs mentioned above. Arbitrum adopts a unique approach that allows for the coexistence of various state hashes. In this approach, if two parties stake on different state hashes at a certain point, a dispute may arise. It is important to determine whether the cause of the dispute is due to a specific point in time when the state hash branched or due to a branching that occurred before then. To solve this, Arbitrum utilizes a rule called the ‘Bisection type protocol‘ to track the origin of the state hash that branched. This process can be imagined as tracing the Merkle tree backward from the point of dispute. While tracing, the transaction that caused the branching of the state hash is found. This transaction is executed on the Ethereum mainnet, and the resulting state hash is compared to determine which one is correct. In other words, Arbitrum adopts an interactive fraud proof method in which the challenger and defender continuously interact to find and resolve issues.

Specifically, Arbitrum’s Bisection type protocol proceeds in the following steps:

  1. Trace the Merkle tree backward from the point of dispute.
  2. Find the transaction that caused the branching of the state hash.
  3. Execute the transaction on the Ethereum mainnet.
  4. Compare the resulting state hash to determine which one is correct.

Through this approach, Arbitrum can allow for different state hashes while efficiently and accurately resolving disputes when they arise.

Arbitrum vs Optimism 

Arbitrum and Optimism are both effective layer 2 solutions that reduce the load on the Ethereum network and improve scalability, and they both use optimistic rollups.

Optimism uses single-round fraud proofs, while Arbitrum uses multi-round fraud proofs. The difference in these fraud proof methods leads to differences in speed and gas fees between the two solutions.

Speed is faster with Optimism, while cost is lower with Arbitrum.

Arbitrum takes longer to perform fraud proofs than Optimistic Ethereum because it requires finding the fundamental branching point on the Merkle tree after a dispute occurs. However, it has the advantage of costing less because it greatly reduces the transactions that need to be directly executed on the Ethereum mainnet.

In conclusion, both Optimism and Arbitrum are effective layer 2 solutions for improving Ethereum’s scalability, but the suitable technology for specific applications differs. Fast and expensive Optimism is suitable for applications that require fast speed, while slow and cheap Arbitrum is suitable for applications that need to save costs.

In fact, Arbitrum is a layer 2 based on Optimism’s technology, so the two have many similarities. However, they have clear differences in the structure of each layer 2 and the way fraud proofs are carried out during the dispute period. Through these differences, it can be said that Arbitrum, despite being a latecomer, has about 2.5 times the scale difference compared to Optimism.

Optimism stores both transaction data and state root, so fraud proofs do not take long. However, due to the fact that these data must be directly brought to the Ethereum mainnet and transactions must be performed, it is relatively expensive.

In this post, we covered Abitrum ONE and Nova, discussing the various verification methods of optimistic rollups, as well as DAC and AnyTrust. In the next post, we will delve into the meaning of the Abitrum token ($ARB) in more detail through Abitrum DAO & Orbit.



3 Line Summary

  • Arbitrum is an optimistic rollup that uses interactive fraud proofs through a bisection type protocol.
  • Arbitrum uses multi-round interactive proving, while Optimism uses single-round interactive proving. Arbitrum has the advantage on the cost side, while Optimism has the advantage on the speed side.
  • Arbitrum Rollup and Arbitrum AnyTrust are protocols that make Ethereum transactions faster and cheaper. DAPPs can be built using the chains that implement these protocols, Arbitrum One and Arbitrum Nova respectively.


Luniverse Rising Web3 in Seoul at KBW2023

Join the Lambda256, the blockchain tech company of Dunamu(Upbit) in South Korea at the side event in Korea Blockchain Week 2023!

​Luniverse, the blockchain infrastructure service of Lambda256 is expanding its ecosystem from private chain to public chains like Ethereum and Polygon supporting more global DApps this year. We are having this event as an opportunity to introduce our partner & rising dapps in Seoul.

​Get ready to connect Luniverse team with rising DApp projects in Seoul, and witness how they are making a difference in the growing web3 industry.

​Registration is open for all Web3 dapps, enthusiast, developers, media, vc, and more!

📍Event Overview

  • ​Date/Time: September 4th 2023, 16:00-20:00

  • ​Venue: Google Startup Campus Seoul (B2, 417, Yeongdong-daero, Gangnam-gu, Seoul)

  • ​Powered by Google Cloud, Aptos, Polygon, Dorahacks

  • ​Among Speakers: Polygon, Aptos, Dorahacks, XPLA, Monoverse, MMZ, Openmetacity, ProjectWITH, Modhaus, Stelsi, Getpip, etc

  • ​Ticket: Free (Invitation-only)


​⏰ Program Overview

16:00 – 16:30 Welcome

16:30 – 17:30 Luniverse & Partner Session

17:30 – 18:30 Panel Discussions of Rising DApps

18:30 – 19:30 Dinner & Networking & Office Hour

​(The program details with the timeline will be sent to the visitors)

​💙  About the host – Lambda256

​Lambda256 is a blockchain tech arm of Dunamu, the operator of Upbit. As a web3 tech company, Lambda256 envisions facilitating the adoption of enterprise blockchain technology to achieve mass adoption. In addition to its own private chain, Luniverse, we have also launched an upgraded version called Luniverse NOVA, which supports public chains like Ethereum and Polygon. We provide a development platform that simplifies DApp development and operation, including a multi-chain API and node services, all provided free of charge. Furthermore, we have developed services such as the movie community NFT platform ‘MMZ’ and the global leading travel rule solution ‘VerifyVASP’.

​💙 About Luniverse

​Luniverse is a Web3 infrastructure service platform that offers innovative technology such as a development environmentAPI, and operation tools that allow users to quickly and easily create blockchain services. The development environment allows all developers and companies to apply blockchain technology to businesses and enter the Web3 space without difficulty. Highly efficient blockchain services can be developed and operated with ease thanks to simple network settings, convenient operating tools, and high-performance chains of over 3000TPS.

​In this year, Luniverse upgraded to Luniverse NOVA, a new version of Luniverse that includes pubic chain infrastructure such as blockchain node servicesMultichain API for Ethereum and Polygon blockchain development, as well as a dashboard and data indexing features required for easy blockchain service operation.

​Website: luniverse.io

​Twitter: https://twitter.com/luniverse_io


​If you were referred to this event by a Google Cloud Partner or event sponsor, your registration information may be shared with that company.

​By participating in this event, you consent to being photographed and/or filmed, and you grant permission for your likeness to be used in promotional and/or marketing materials.

​Inquiry: support@lambda256.io

Luniverse NOVA X Arbitrum 01 What is Arbitrum & Why ?

This series of posts is produced in collaboration with ART: Aslan Research Team, a research team within the Aslan Academy, a blockchain research organization.

As part of Luniverse NOVA’s support of the Arbitrum chain, this series of posts is designed to help you better understand Arbitrum. You don’t need to have a complex knowledge of blockchain, we’ve organized the content in a way that makes it easy to understand.

In this article, we’ll cover how Arbitrum came to be, the features of the Arbitrum Chain, its main products and technologies, the mainnet and testnet, and an overview of Arbitrum’s history and roadmap.

1-1. Background of the Birth of Arbitrum

Ethereum is currently the undisputed No. 1 layer 1 blockchain. However, as we discussed in our last Polygon article, Ethereum suffers from the Trilemma: the tradeoff between scalability, decentralization, and security. Since Ethereum is already the best at decentralization and security, scalability is its biggest problem, which is why we’re seeing a number of L2 solutions like Polygon and Arbitrum to overcome this scalability issue.

As we covered in a previous article, Polygon is a Layer 2 scaling solution that emerged to overcome Ethereum’s scalability issues. As mentioned above, the Ethereum network has high transaction fees and processing times, as well as scalability issues, which limits the variety of users and the development of decentralized applications (DApps). To solve these problems, Polygon aims to improve Ethereum’s scalability, reduce costs and latency by using Plasma technology as a foundation. 

Like Polygon, Arbitrum aims to reduce the high transaction fees and processing times of the Ethereum network. However, unlike Polygon, which utilizes plasma technology, Arbitrum aims to improve Ethereum’s scalability by using technology based on roll-ups.

Other Solution – Polygon(Plasma) | Arbitrum(Roll-up)

Arbitrum came about in the same vein as Polygon, which we discussed earlier, to solve Ethereum’s scalability problem. The difference is that Polygon solved it through plasma, and Avitrum solves it through rollups.

While Polygon PoS has achieved incredible gas savings without sacrificing Ethereum’s security, the underlying problem with Plasma is data availability, which is why we’re seeing a trend toward focusing resources on things like L2 scaling and ZK rollups to find a better solution.

Polygon: Plasma

Polygon PoS is a public chain on the Polygon network that exists as a sidechain to Ethereum, utilizing the Proof-of-Stake (PoS) consensus algorithm and Plasma to improve the performance and scalability of the Ethereum network. A more detailed description of Plasma can be found in the Plasma section of our previous article.

While Polygon PoS has achieved incredible gas savings without sacrificing Ethereum’s security, the underlying problem with Plasma is data availability, which is why we’re seeing a trend toward focusing resources on things like L2 scaling and ZK rollups to find a better solution.

Arbitrum: Roll-up

Arbitrum is another Ethereum Layer 2 scaling solution, and it’s a protocol that uses rollups.


Rollups are a way to process transactions on Layer 2 and send only the final result to Layer 1, the Ethereum mainnet, to reduce the load on the mainnet and improve throughput. There are two main types of rollups: optimal rollups and ZK rollups.

1) Optimistic Rollup

Transaction verification is performed using a proof-of-fraud approach. The data is assumed to be correct, and validators have a period of time to dispute any incorrect data they find. After the challenge period, the data is assumed to be correct and the state is finalized. This approach supports common smart contracts and has low initial implementation costs, but can incur high gas costs during the challenge and verification process.

2) ZK Rollup

Transaction validation is performed using the proof-of-validity method. The sequencer submits a zero-knowledge proof along with the transaction data to Ethereum to verify the correctness of the data. Incorrect data is rejected from the start, with no appeal period and fast status finalization. ZKRollups offer a higher level of security and lower gas costs, but can be limited in their support for complex smart contracts.

Avitrum’s rollups perform transaction validation using the fraud proof approach of optimal rollup technology. Optimal rollups assume that the data is correct, and validators have a period of time to dispute any incorrect data they find, after which the data is considered correct and the status is finalized.

Offchain Labs, the developers of Avitrum, summarize the top reasons for choosing Optimal Rollups.

  1. fulfills user-demanded properties: Optimal rollups provide the properties users want, such as safety, guaranteed progress, visibility, and fast finality, in a trustless manner.

  2. Reduces network centralization: ZK Proofs are expensive to process, and often require dedicated hardware or parallel processing to fully participate in the ZK protocol, which can increase network centralization. Optimistic rollups, on the other hand, reduce these issues.

  3. Low cost: Compared to complex ZK proofs with high off-chain costs, the cost of running the code is much lower with optimal rollups compared to computing complex cryptographic proofs. This results in a significant operational cost advantage.

See also: Offchain Labs

Like Polygon, Avitrum aims to solve Ethereum’s trilemma problem, and while Polygon utilizes plasma technology, Avitrum aims to improve Ethereum’s scalability by utilizing rollup technology. Avitrum specifically uses optimal rollups for transaction verification via fraud proofs, reducing initial implementation costs and supporting common smart contracts.

In conclusion, while these two technologies have different approaches, they both share the common goal of improving the Ethereum network by reducing its load and increasing its efficiency.

1-2. Arbitrum Features and Technology

The first permissionless Ethereum layer 2 rollup with full Ethereum smart contract functionality

Arbitrum was the first of many L2s to launch an L2 mainnet in 2020, and with its Stylus and WASM virtual machines, it offers EVM parity, faster speeds, and lower gas costs. This makes it the L2 mainnet of choice for many Ethereum developers.

In fact, as you can see in the chart, it is currently the most active Layer 2 network with a market share of 60.83%.

Arbitrum Nitro → Lower gas costs, EVM compatibility

Arbitrum Nitro is the technology stack used in Arbitrum One and Nova, and is built around four main concepts.

  1. Sequencing, Followed by Deterministic Execution : Sequencing, followed by Deterministic Execution.
    Transactions are processed using a method called Sequencing followed by Deterministic Execution. It uses a two-step strategy where transactions are first organized into a single ordered Sequence, which is then processed by a Deterministic state transition function.
  1. Geth at the Core: Using Geth as the core code (EVM compatibility)
    Nitro compiles the core code of the go-ethereum (“Geth”) Ethereum node software to support Ethereum’s data structures, formats, and virtual machines. Geth is the core code of go-ethereum, which allows Nitro to support Ethereum’s data structures, formats, and virtual machines, and ensures high compatibility with Ethereum.
  2. Separate Execution from Proving : Separate Execution from Proving (Utilizing WASM)
    Nitro introduces ‘Separate Execution from Proving’ to compile the same source code twice. The first time is the native code optimized for speed on Nitro nodes, and the second time is the WASM code optimized for portability and security, which is used for proof.
  3. Optimistic Rollup with Interactive Fraud Proofs: Optimistic Rollup with Interactive Fraud Proofs.
    Settling transactions on the layer 1 Ethereum chain. This method utilizes the Optimal Rollup protocol with interactive fraud proofs pioneered by Avitrum.

References: Avitrum official dox

Arbitrum One → The first EVM Rollup to achieve the second stage of decentralization

Arbitrum One is an L2 optimal rollup chain that implements Arbitrum’s rollup protocol. The chain serves to reduce Ethereum’s gas costs by bundling multiple transactions and publishing them to Ethereum’s L1 chain at once. It relies on an ‘Optimistic execution’ approach, which assumes that all transactions are processed correctly by default. As a result, validators who detect incorrect transactions are rewarded. In this way, it achieves both efficient transaction processing and reliability.

In addition, Arbitrum One utilizes the Arbitrum Nitro technology stack. The Nitro technology stack leverages a Geth-based architecture to enable fast, low-cost transactions while maintaining compatibility with Ethereum through calldata compression, implementation of isolated contexts, and compatibility with Ethereum L1 gas. As such, Arbitrum One is an L2 optimal rollup chain that enables Ethereum dApps to be built and run at an efficient cost.


3 Lines Summary

  • Arbitrum is the first permissionless Ethereum L2 EVM rollup scaling solution and is the most active L2 network. EVM equivalence is achieved through Stylus and WASM, and Rollup employs an Optimistic Rollup approach,
  • Arbitrum Rollup and Arbitrum AnyTrust are protocols that make Ethereum transactions faster and cheaper. DAPPs can be built using Arbitrum One and Arbitrum Nova, chains that implement these protocols respectively.
  • Improve decentralization and scalability through Arbitrum DAO and Arbitrum Orbit. DAO achieves the above objectives through the ARB token and Orbit through the introduction of the L3 concept.

Luniverse Now Supports Arbitrum!

Luniverse now supports Arbiturm on our Node Service!🎉🎉 You can now use the ethereum layer 2 scaling solution, Arbitrum node and APIs on Luniverse.

Additionally, explore the new features updated on Luniverse such as  TxAction Callback SecurityTx Monitoring that allows you to operate your dapps easy and fast!

Luniverse Now Supports Arbitrum Node!

If you are considering blockchain service development using the Arbitrum, if setting up dev environment such as blockchain nodes from scratch and integrating them into your services seems challenging, you can use the Arbitrum node service provided by Luniverse to create blockchain services easy and fast.

Now, the Luniverse multi-chain node service supports the Ethereum Layer 2 scaling solution, Arbitrum. Explore the Arbitrum JSON-RPC API offered by Luniverse!

Move to Arbitrum JSON-RPC

About Arbitrum

Arbitrum, a layer 2 solution, enhances Ethereum smart contracts by improving speed, scalability, and privacy. Developers can seamlessly run unmodified Ethereum Virtual Machine contracts and transactions on this secondary layer while benefiting from Ethereum’s security. This addresses Ethereum’s current smart contract limitations, including inefficiency and high costs, which have hampered user experience. Arbitrum utilizes transaction rollups to batch and execute transactions on a scalable layer 2 sidechain, reducing Ethereum’s computational burden and enabling innovative layer 2-based DApps. Developed by Offchain Labs, led by blockchain experts Ed Felten, Steven Goldfeder, and Harry Kalodner, Arbitrum aims to enhance cryptocurrency capabilities through scalable solutions.

Luniverse Changelog

Luniverse’s new updates – What has changed?

TxAction Callback Security

A security element has been added to the TxAction Callback function provided by Luniverse. Now users can check if the response is the actual response sent by Luniverse. Details can be found by clicking on the link.

Move to TxAction Callback Security

Tx Monitoring

You can monitor your own transactions using the Luniverse console. You can easily check the necessary information by using various filtering values such as period, success, and executed method. Details can be found by clicking on the link.

Move to Tx Monitoring

Luniverse Scan CSV download

Tx data for tokens can be extracted from Luniverse Scan in CSV file format. (If you open the file with Excel or Numbers, different values may appear due to automatic unit conversion. It is most accurate to check by running it in an application that does not convert units, such as Notepad.)

Luniverse Multichain Web3 API Response Field

listTokenMetadataBySymbolslistTokenMetadataByContracts Description, logo, websites, technicalDocs, and launchedAt have been added as API response fields. Now, you can utilize more diverse metadata using the Luniverse Multichain API.

Luniverse dev team is continuously working on improving its platform features for blockchain development. Stay tuned for our upcoming updates!