Introducing Arbitrum

Arbitrum is an open-source cryptocurrency platform that we’re building at Offchain Labs.

If you’re a smart contract developer, why should you use Arbitrum, rather than Ethereum or some other platform? Because Arbitrum is scalable, private, and trustworthy, while remaining compatible with the languages and tools that you’re probably already using. No other solution has this combination of benefits.

Compatibility with Ethereum

Arbitrum is compatible with Ethereum, and runs on top of Ethereum. Like on Ethereum, you write your dapp in Solidity, and you use the open source Arbitrum compiler to compile your Solidity code to run on Arbitrum. You can also transfer Ether or any other Ethereum-based token back and forth between Ethereum and Arbitrum.

Scalability

In normal operation, decentralized apps (dapps) only have to touch the main chain on startup or when they send or receive currency outside of Arbitrum. Other interactions can happen entirely offchain, with quick turnaround and guarantees of finality. Even in abnormal cases, the burden on the main chain is small compared to other solutions.

Privacy

Only the participants who validate a dapp’s execution need to know what is in the dapp’s code or storage. All that is published on-chain are cryptographic hashes of the dapp’s state, and information about the dapp’s public actions such as sending and receiving calls, messages, and currency. The dapp developer gets to choose their own validators.

Users of a dapp can be given information about its internals if desired, and they can verify the information if they receive it, but this disclosure is strictly optional, depending on the needs of each dapp.

AnyTrust Guarantee

Unlike many other sidechain or private chain solutions, Arbitrum guarantees correct execution as long as any one validator of a dapp is acting honestly — even if all of the other validators are colluding to (try to) cheat. Many other approaches require majority-honest or two-thirds-honest assumptions, or require moving the entire state of a contract to the main chain in case of a dispute.

The AnyTrust Guarantee is especially nice if you are a validator of a dapp. You can stand up for your own rights and force the dapp to give you the behavior and currency that you deserve, no matter what anybody else does. If all of the parties interested in a dapp are allowed to be validators, then everybody has a guarantee of correct behavior.

How do we accomplish all of this? Stay tuned. In future posts we’ll talk about how Arbitrum works and how you can use it.