Hemi
Overview
Status
Mainnet
Type
Alt. Rollup
Fee Token
ETH
BTC Supply
₿0
Hemi is a blockchain that is building compatibility with bitcoin and Ethereum. It is built on the OP Stack and has an official bridge program hosted on Ethereum. It additionally has an official bridge program on bitcoin securing BTC backing HemiBTC.
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
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.
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.
Bridge program(s) do not have a functional proof system
The bridge program(s) do not have a functional proof system. A centralized proposer can submit a malicious state transition and steal funds from the bridge.
Categorization
The project anchors its state to bitcoin, but does not meet our criteria to be a sidesystem
The project does not have an enshrined bitcoin bridge that meets our sidesystem standards. Our standards require sidesystem's enshinred bridge programs to have at least 5 signers with 4 of those signers being external to the project's primary development organization.
Trust Assumption Review
BTC Custody
Very High
🛑
The signers securing BTC backing HemiBTC have not been officially disclosed
BTC backing HemiBTC is secured in a single-signature bitcoin address. Hemi claims that they use a threshold signature scheme to move funds from this address, but the specific siganture scheme, and participating signers, have not been officially disclosed.
The signers for this bridge have not been disclosed
The signers for this bitcoin two-way peg have not been disclosed. The signers have unilateral control of funds backing this wrapped asset. Collusion can result in loss of user funds. There is no reputational damange for these signers if they act maliciously.
Learn more about Hemi hemiBTC'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
Very High
🛑
Hemi blocks are produced by a centralized sequencer
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 cannot sequence their own transactions if the sequencer goes down or censors them.
Finality Guarantees
Medium
⚠️
Hemi state updates are finalized offchain. The network anchors its state to bitcoin
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.
After this state is generated, nodes participating in Hemi's Proof-of-Proof consensus submit the latest state root to bitcoin.
After this state is generated, nodes participating in Hemi's Proof-of-Proof consensus submit the latest state root to bitcoin.
Note on Hemi's Proof-of-Proof consensus
While Hemi's anchors its state to bitcoin, the network is currently managed by a centralized operator. The operator is unable to revert Hemi's state after Hemi full nodes compute a new state root. This is independent of any additional finality guarantees potentially provided by bitcoin.
Additional Contracts
Address securing BTC backing HemiBTC
Specific address securing BTC backing HemiBTC. It is unknown if this address is managed by a single entity or multiple entities via a threshold signature scheme.
Bridge contract escrowing wBTC & tBTC
This bridge contract does not have a functional proof system and can be upgraded by a 3/8 multisig.
Bridge contract escrowing mBTC
This bridge contract can be upgraded by a 3/7 multisig.
Additional Considerations
No public dashboards on PoP miners available
The project has not published mainnet dashboards related to active PoP miners. It is unknown how many miners are posting state roots to bitcoin.
Bitcoin Security
Hemi checkpoints its state to bitcoin
The network's security is independent of bitcoin and reliant on its own consensus mechanism. Its checkpoint mechanism, however, ensures that after a transaction including a checkpoint reference is included on bitcoin, the network's state cannot be reverted without reorging bitcoin.
ETH token used to pay fees
Fees to network operators are paid in an alternative token.
No MEV introduced to Bitcoin
The network does not introduce any MEV on the Bitcoin L1. Users trust the sequencer to not reorder their transactions to extract MEV.
Hemi does not contribute to the security budget
The network does not currently contribute to the Bitcoin security budget.
Use Cases
Onchain applications
Onchain applications are supported. Onchain applications include borrowing and lending protocols, onchain exchanges (commonly referred to as decentralized exchanges), and more. These applications are supported with more expressive smart contract environments.
Technology
Proof-of-Proof consensus
Hemi's Proof-of-Proof (PoP) consensus is a bitcoin anchoring mechanism. After Hemi full nodes compute a new state root, PoP nodes publish this state root to bitcoin. After this state root is published, a Bitcoin Finality Governor queries bitcoin, finds the appended state root, and considers Hemi's blocks final.
The network is EVM-compatible
The network 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. The network's specific node implementation additionally executes a bitcoin light client.
Knowledge Bits
This network is a layer 2 for Ethereum. For a view into the technology from an Ethereum perspective, head to L2Beat for their review.