The Optimism page of Bitcoin Layers is under development.

Bitcoin Layers' focuses its efforts on reviewing protocols that claim to be a bitcoin layer and BTC wrappers that live on alternative chains. Alternative network provide a snapshot into the network architecture, but largely focus on review related to BTC wrappers on the network. If the network is an Ethereum L2, we recommend heading to L2Beat for a deeper dive into the architecture.

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Optimism

Overview

Status

Mainnet

Type

Alt. Rollup

Fee Token

ETH

BTC Supply

₿0

Optimism is an Ethereum rollup that that supports a variety of wrapped BTC tokens.

CUSTODY

DATA AVAILABILITY

OPERATORS

FINALITY ASSURANCE

BTC Supply

Total supply per day

Supplycoming soon

TVL Data Coming Soon

We're currently gathering and building data infrastructure for this network. TVL analytics will be available soon.

Token Contracts

Token Contracts Coming Soon

We're working to collect the various BTC-backed token contracts for this network. Contract addresses will be available soon.

Risk Summary

Bridge contracts are upgradeable

A centralized party can immediately upgrade specific system contracts. This risk may be relevant to BTC-backed tokens locked in the layer's official bridge contract.

All BTC pegs have custodian trust assumptions

All BTC backing wrapped tokens on this network are ultimately secured by custodians. Users trust that these custodians will not misappropriate funds and keep their assets pegged 1:1. Each custodian has their own risks. Learn more in the trust assumptions review section.

Another data availability layer is used

Data related to the network's state is made available by another consensus network. The network's state cannot make progress if the data availability layer withholds the data. If the network cannot make progress, user funds can be frozen.

A centralized entity is the network operator

The network is operated by a centralized operator. If this operator goes offline, the network can be halted which can freeze user funds. Please see the trust assumptions to learn if their is a fallback mechanism for liveness failures.

Trust Assumption Review

BTC Custody

High

🚨

Users trust the Threshold Network to keep tBTC backed and a 9 member federation to manage tBTC's bridge between Base and Ethereum

tBTC's peg with bitcoin is managed by the Threshold Network, a distributed but permissioned two-way peg. This group of signers participate in a threshold signature scheme to secure the BTC that backs tBTC.

This bridge is managed by a 6/9 federation. Bitcoin users trust that 6 of the 9 members of this federation do not collude and steal user funds.

Learn more about Threshold tBTC's custody model→

Data Availability

Medium

⚠️

Data is stored and made available by Ethereum full nodes

The data for network's state is made available by Ethereum full nodes. Anyone can run an Ethereum node and verify the state of the network.

Network Operators

Medium

⚠️

Optimism blocks are produced and proposed by a centralized operator, but users can propose their own state updates in the event of censorship or liveness failures

The network's sequencer is managed by one entity. The sequencer can censor transactions and can also cause liveness failures if it goes down. Users can bypass the sequencer and send their transactions directly to its parent chain. Users can also self-propose their own state transition, and exit the network to its parent chain.

Finality Guarantees

Medium

⚠️

Optimism state transitions finalize by updating its state based on data posted to Ethereum

The network's state is updated offchain by nodes who apply state transition logic over the data made available by its data availability layer. After a new state is generated, a state root may be posted to bridge programs.

Finality is not necessarily through the lens of a validating bridge

The network is an alternative rollup. This means it uses another blockchain for data availability. From the view of its full nodes, the rollup's state is finalized after it it validates state updates published to the data availability layer. Therefore, the network's finality assurances are that of its data availability layer (assuming the node operation is permissionless). A state root may be additionally posted to the data availability layer to finalize bridge programs, but this is not a guarantee of finality. This guarantee ensures the network's bridge programs are secure and can permit withdrawals based on the network's state. This only applies to tokens that are locked in these specific's bridge programs. See the BTC custody section for more information.

Partial Review Available

This project is currently undergoing a partial review. The trust assumptions and risk analysis above are available, but additional sections are still in progress.

Additional analysis and documentation will be added once our review is complete.