AltLayer has launched BLITZ, a fast-finality network for Arbitrum Orbit chains, developed in collaboration with Babylon. BLITZ addresses slow finality issues in rollups by leveraging BTC staking for security, providing crypto-economic security to Orbit chains. It offers fast-finality, crypto-economic security, and native BTC staking. BLITZ uses Babylon's staking protocol, allowing BTC holders to stake natively on the Bitcoin chain. The network is designed to support new Orbit chain deployments and seeks involvement from operators as finality providers.

BLITZ leverages BTC staking through Babylon<figure><img src='https://sosovalue.s3.us-west-2.amazonaws.com/sosovalue/web3image/24/11/30/1uostt4spo4j.png'/></figure>We are thrilled to announce the launch of BLITZ — a fast-finality network for Arbitrum Orbit chains. BLITZ is the first decentralized network built to serve Orbit chains that leverage BTC staking for security via Babylon. It has been developed by AltLayer in collaboration with the Babylon team.BLITZ provides Arbitrum Orbit chains with fast-finality, addressing the slow finality issues prevalent in rollups (it still takes ≈13 min for an Ethereum block to finalize!) It utilizes BTC as economic collateral for security via Babylon (wherein L2 blocks with votes backed by BTC are considered “final”) providing crypto-economic security to the chains.Scroll down for a deep dive into why faster-finality is the need of the hour, how AltLayer’s BLITZ design was conceived and built, and what it will do for Orbit L2s and its ecosystem.Why Faster Finality for Arbitrum Orbit Chains?Orbit chains are an instance of an optimistic rollup that rely on fraud proof systems for settlement. Users and dApps on an Orbit chain get two types of transaction finality:<ol><li>Soft finality offered by the rollup sequencer.</li><li>Hard finality when rollup transactions/states get settled on Ethereum.</li></ol><figure><img src='https://sosovalue.s3.us-west-2.amazonaws.com/sosovalue/web3image/24/11/30/hby5tt4spo38.png'/></figure>While Ethereum is the most decentralized network with over <a href="https://beaconscan.com/stat/validator" target="_blank">1.6M validators</a>, it’s also the network with the <a href="https://defillama.com/chains" target="_blank">most liquidity</a> and therefore, it is not surprising that Ethereum is a popular settlement layer of choice for many Arbitrum Orbit chains. However, Ethereum as a network is not the fastest of all to finalize and settle transactions.Currently, it takes about 13 minutes for an Ethereum block to finalize. This lack of quick finality directly impacts Orbit chains as by design, they are tied to the finality and security of the underlying Ethereum chain.As a result, app-specific Orbit chains that are designed to serve latency-sensitive applications such as games and social apps often end up relying on the promise provided by the sequencer that at some point in the future, it will post L2 transactions on-chain. However, as centralized sequencers have no economic stake, the soft finality guarantee offered by them has no economic backing.Beyond slowness in finalizing simple rollup transactions, the impact of finality goes much deeper as it affects cross-rollup bridging, resulting in dependency on centralized exchanges or non-validating bridges that rely on liquidity locked in contracts, which in itself creates new risks for end users. More generally, this also results in liquidity fragmentation across rollups.<figure><img src='https://sosovalue.s3.us-west-2.amazonaws.com/sosovalue/web3image/24/11/30/dgastt4spo8m.png'/></figure><h4>Introducing BLITZ</h4>BLITZ is a decentralized fast finality layer that leverages BTC as economic collateral for security via Babylon. Operators stake BTC and provide signed commitments on an L2 block even before the block gets committed to Ethereum. L2 blocks with votes back by a sufficient amount of BTC can then be considered final from a crypto-economic perspective.<figure><img src='https://sosovalue.s3.us-west-2.amazonaws.com/sosovalue/web3image/24/11/30/z2rgtt4spot5.png'/></figure>At the heart of BLITZ is Babylon’s staking protocol, which allows BTC holders to stake BTC natively on the Bitcoin chain.Arbitrum Orbit chains can benefit from BLITZ as the design offers:<ol><li>Fast-Finality: To combat the slow finality issues with optimistic rollups;</li><li>Crypto-economic security: The finality provided comes with crypto-economic guarantees;</li><li>Native BTC staking: Using BTC as economic collateral by leveraging Babylon’s BTC staking protocol.</li></ol>How BLITZ WorksBLITZ taps onto some of the earlier designs for faster finality that use BTC staking, such as the <a href="https://x.com/babylonlabs_io/status/1800396017571164597" target="_blank">forkless rollup design</a>, whereby, the rollup sequencer and/or a dedicated network of finality providers (FPs) stakes BTC as economic collateral, and signs L2 blocks using a special signature scheme called extractable one-time signatures (EOTS). The signed L2 blocks can then be used to give assurances to stakeholders. If the sequencer signs another conflicting L2 block at the same height and attempts to equivocate, then, the two conflicting L2 blocks will allow any party to extract the underlying private key, effectively slashing the staked BTC.AltLayer has built a variation of the forkless rollup design, and tailored our expertise around fast-finality to suit Arbitrum chains in the form of a fork of the Orbit stack. In this model, FPs offer their services to a given Orbit chain. Each FP is unique to one Orbit chain. BTC holders can delegate their native BTC to FPs, who enjoy voting power proportional to the amount of BTC delegated to them.<figure><img src='https://sosovalue.s3.us-west-2.amazonaws.com/sosovalue/web3image/24/11/30/tuaott4spovr.png'/></figure>The signed blocks are instead sent to the Babylon chain for verification, vetting whether they are from a set of registered FPs, whether they are valid and backed by BTCs. A signature submitted by a FP corresponds to a certain number of votes that is proportional to the total amount of BTC delegated to it. A block with votes backed by &gt;⅔ BTC staked is considered finalized.Getting Involved with BLITZBLITZ is live and ready to use. It is designed to support any new deployment of an Orbit chain. We are looking for both orbit chains interested in making use of BLITZ as well as operators who wish to get involved as finality providers to reach out to us via &lt;support@altresear.ch&gt;*******<img src=''/><hr /><a href="https://blog.altlayer.io/altlayers-fast-finality-network-for-arbitrum-orbit-chains-blitz-is-now-live-5e511ed976d4" target="_blank">AltLayer’s fast-finality network for Arbitrum Orbit chains “BLITZ” is now live</a> was originally published in <a href="https://blog.altlayer.io" target="_blank">AltLayer</a> on Medium, where people are continuing the conversation by highlighting and responding to this story.

AltLayer Launches BLITZ: A Fast Finality Network for Arbitrum Orbit Chain