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Fraud proof system is currently under development. Users need to trust block Proposer to submit correct L1 state roots.

Boba is an L2 Ethereum scaling & augmenting solution built by the Enya team as core contributors to the Boba Foundation. Boba is an EVM-compatible Optimistic Rollup chain forked from Optimism. Two notable features are fast withdrawal facility that allows users to remove funds immediately without waiting for the end of the 7-day fraud proof window. This facility is using funds from liquidity providers. The second is Hybrid Compute technology that enables Ethereum developers to build dApps that trigger code executed on web-scale infrastructure. Boba Network operates on multiple Layer 1 blockchains.

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Risk summary


Fraud proofs are in development

Ultimately Boba Network will use fraud proofs to enforce state correctness. This feature is currently in development and the system permits invalid state roots. Users have the ability to run a validator software and compute valid state roots locally, but cannot act on them on chain.

  • Funds can be stolen if an invalid state root is submitted to the system (CRITICAL).

  1. The incentive contract for verification proofs is disabled - Boba FAQ
  2. Checking Boba Mainnet for Fraud - Boba Optimism repository

All transaction data is recorded on chain

All executed transactions are submitted to an on chain smart contract. The execution of the rollup is based entirely on the submitted transactions, so anyone monitoring the contract can know the correct state of the rollup chain.

  1. Data Availability Batches - Paradigm Research
  2. Canonical Transaction Chain - Boba documentation


The system has a centralized sequencer

While proposing blocks is open to anyone the system employs a privileged sequencer that has priority for submitting transaction batches and ordering transactions.

  • MEV can be extracted if the operator exploits their centralized position and frontruns user transactions.

  1. Boba operates the only "Sequencer" node - Boba FAQ

Users can force any transaction

Because the state of the system is based on transactions submitted on-chain and anyone can submit their transactions there it allows the users to circumvent censorship by interacting with the smart contract directly.

  1. Canonical Transaction Chain - Boba documentation


Regular exit

The user initiates the withdrawal by submitting a transaction on L2. When the block containing that transaction is finalized the funds become available for withdrawal on L1. The process of block finalization usually takes several days to complete. Finally the user submits an L1 transaction to claim the funds. This transaction requires a merkle proof.

  • Funds can be frozen if the centralized validator goes down. Users cannot produce blocks themselves and exiting the system requires new block production (CRITICAL).

  1. The Standard Bridge - Boba documentation

Fast exit

Users can initiate a fast exit which makes use of liquidity pools, and charges a small fee for the convenience. Users funds can then be withdrawn on L1 after only minutes.

  1. The LP Bridge - Boba documentation

Other considerations

EVM compatible smart contracts are supported

Boba Network is pursuing the EVM Equivalence model. No changes to smart contracts are required regardless of the language they are written in, i.e. anything deployed on L1 can be deployed on Boba Network.

  1. Introducing EVM Equivalence

Permissioned Addresses

The system uses the following set of permissioned addresses:

This address is the owner of the following contracts: OVM_L1CrossDomainMessenger, L1StandardBridge, LibAddressManager. This allows it to censor messages or pause message bridge altogether, upgrade bridge implementation potentially gaining access to all funds stored in a bridge and change the sequencer, state root proposer or any other system component (unlimited upgrade power).

Sequencer 0xfa46…c57F

Central actor allowed to commit L2 transactions to L1.

State Root Proposer 0x5558…bE80

Central actor to post new L2 state roots to L1.

Smart Contracts

A diagram of the smart contract architecture
A diagram of the smart contract architecture

The system consists of the following smart contracts:

CanonicalTransactionChain 0xfBd2…c3Db

The Canonical Transaction Chain (CTC) contract is an append-only log of transactions which must be applied to the OVM state. It defines the ordering of transactions by writing them to the CTC:batches instance of the Chain Storage Container. CTC batches can only be submitted by OVM_Sequencer. The CTC also allows any account to enqueue() an L2 transaction, which the Sequencer must eventually append to the rollup state.

StateCommitmentChain 0xdE73…41Ec

The State Commitment Chain (SCC) contract contains a list of proposed state roots which Proposers assert to be a result of each transaction in the Canonical Transaction Chain (CTC). Elements here have a 1:1 correspondence with transactions in the CTC, and should be the unique state root calculated off-chain by applying the canonical transactions one by one. Currenlty olny OVM_Proposer can submit new state roots.

ChainStorageContainer-CTC-batches 0x1714…1231
ChainStorageContainer-CTC-queue 0x5f00…CD8d
ChainStorageContainer-SCC-batches 0x1399…7d93
BondManager 0x6066…b627

The Bond Manager contract will handle deposits in the form of an ERC20 token from bonded Proposers. It will also handle the accounting of gas costs spent by a Verifier during the course of a challenge. In the event of a successful challenge, the faulty Proposer's bond will be slashed, and the Verifier's gas costs will be refunded. Current mock implementation allows only OVM_Proposer to propose new state roots. No slashing is implemented.

The L1 Cross Domain Messenger (L1xDM) contract sends messages from L1 to L2, and relays messages from L2 onto L1. In the event that a message sent from L1 to L2 is rejected for exceeding the L2 epoch gas limit, it can be resubmitted via this contract's replay function.

The L1 Cross Domain Messenger (L1xDM) contract that allows permissioned relayer to relay messages from L2 onto L1 immediately without waiting for the end of the fraud proof window. It is used only for L2->L1 communication.

L1MultiMessageRelayer 0x5fD2…070B

Helper contract that allows for relaying a batch of messages using L1CrossDomainMessenger.

L1MultiMessageRelayerFast 0x2d61…9622

Helper contract that allows for relaying a batch of messages using L1CrossDomainMessengerFast.

Liquidity Pool manager for fast withdrawal facility. This contract can store any token

Lib_AddressManager 0x8376…F089

This is a library that stores the mappings between names such as OVM_Sequencer, OVM_Proposer and other contracts and their addresses.

Main entry point for users depositing ERC20 tokens and ETH that do not require custom gateway. This contract can store any token

Standard NFT bridge.

The current deployment carries some associated risks:

  • Funds can be stolen if a contract receives a malicious code upgrade. There is no delay on code upgrades (CRITICAL).

Social mediaboba.network/#newsboba.network/blogwww.enya.ai/company/media@bobanetworkbobanetworkdiscord.gg
Source codegithub.com/bobanetwork/boba


Boba launches L2 on BNB

2022 Nov 1st

Boba launches on BnB.

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Call data compression

2022 Oct 8th

The Boba Tree From (v0.1.0) release introduces Brotli compression for call data.

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Boba launches L2 on Avalanche

2022 Sep 21st

Boba launches on Avalanche.

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Boba launches L2 on Moonbeam and Fantom

2022 Jun 2nd

Boba launches on Moonbeam and Fantom.

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Hybrid Compute

2022 Mar 18th

Boba’s proprietary technology enables dApps that trigger code executed on web-scale infrastructure.

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BOBA Token launched

2021 Nov 18th

BOBA token launched by OMG Foundation.

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Mainnet launch

2021 Sep 20th

Layer 2 Optimistic Rollup based on the Optimism codebase is live on Ethereum.

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