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BOB

Status
Mainnet
Type
Alt. Rollup
Fee Token
ETH
BTC Supply
₿0
BOB is a rollup that serves as an application layer for bitcoin. They have launched as a rollup on top of Ethereum, with plans to derive more security from bitcoin over time.
CUSTODY
DATA AVAILABILITY
OPERATORS
FINALITY ASSURANCE
Trust Assumption Review
BTC Custody
Very High
🛑
Threshold tBTC
BTC users trust that tBTC will remain backed on Ethereum, and that the BOB bridge will not steal their funds
tBTC is minted on BOB via its official Ethereum bridge. tBTC on Ethereum is backed by BTC managed by the Threshold Network.

Users trust that the bridge operators will not steal their BTC, the BOB proposer to not publish a malicious, unchallenged state transition, or the admin controlling the bridge to create a malicious smart contract upgrade.

In the event of a malicious smart contract upgrade, there is no exit window for BOB users. This means that the admin behind the bridge can steal all funds in the official bridge.

For more information on the Threshold Network & tBTC, click here..
Data Availability
Medium
⚠️
Data is stored and made available by Ethereum full nodes
The data for BOB’s state is stored on the Ethereum blockchain. Anyone can run an Ethereum node and verify the state of BOB.
Network Operators
High
🚨
BOB blocks are produced and proposed by a centralized operator, but forced inclusion to Ethereum L1 possible
Currently, BOB’s sequencer is managed by one entity. The BOB sequencer can censor transactions and would also cause liveness failures if it went down. Users can bypass the sequencer and send their transactions directly to the Ethereum L1. Users do, however, trust that a permissioned proposer will publish the latest state root on the Ethereum L1, permitting withdrawals.
Finality Guarantees
Very High
🛑
BOB state transitions finalize on Ethereum, but proposer role is whitelisted
BOB's state is updated offchain. BOB state transitions, related to its official bridge, are finalized on Ethereum. Only a whitelisted proposer is able to publish state updates to Ethereum. If the BOB proposer goes offline, then users of the rollup would be unable to update BOB's state relative to its official bridge.
Bitcoin Security
BOB does not inherit any security from Bitcoin
In its current state, BOB does not inherit security from Bitcoin.
ETH token used to pay fees
BOB users pay sequencer fees in ETH. BOB operators also pay DA fees in ETH.
No MEV introduced to Bitcoin
BOB does not introduce any MEV on the Bitcoin L1. Users trust the BOB sequencer to not reorder their transactions to extract MEV.
BOB does not contribute to the security budget
BOB does not currently contribute to the Bitcoin security budget.
🚨 Project is not a sidesystem
This project will be moved to the Alternative category
Projects that do not meet our requirements to be considered a sidesystem will be moved to the Alternative category. They have until June 30th to implement the technical requirements to be considered a sidesystem.
Withdrawals
Proposer role centralized and permissioned. BTC users must withdraw to Ethereum L1 before withdrawing to Bitcoin
Users can bypass the sequencer and submit withdrawal requests directly to the Ethereum L1. However, they cannot force-exit as the self-proposing is not enabled. Users rely on the proposer to post updated state roots to Ethereum to ensure withdrawals can be processed. Withdrawals from BOB's official bridge to Ethereum take 7 days to finalize.

Once on the Ethereum L1, users can then redeem their BTC on Bitcoin via the two-way peg mechanism that their BTC synthetic is supported by.

Users primarily trust bridge operators to permit withdrawals back to the Bitcoin mainchain.
Technology
Ethereum Virtual Machine
BOB uses an EVM-compatible virtual machine. The Ethereum Virtual Machine is software responsible for smart contract execution for a number of blockchains, namely the Ethereum Network. It uses Solidity/Vyper as its code and is the dominant environment for smart contract execution in the cryptocurrency ecosystem. BOB is EVM-compatible, which means that a developer from Ethereum would have less difficulty deploying their applications on BOB compared to other execution environments.
Use Cases
Onchain applications
Onchain applications are supported. Onchain applications including borrowing and lending protocols, onchain exchanges (commonly referred to as decentralized exchanges), and more. These applications are supported with more expressive smart contract environments.
Source Code
Under review
We are reviewing if BOB's node software is open-source.
Knowledge Bits
Learn more