Detailed Explanation of the Working Principle and Development Status of Cosmos Cross-Chain Bridge Gravity Bridge
Gravity Bridge will drive the ecosystem into the Cosmos DeFi era.Source: Cosmos Blog
Original Title: “Everything You Need to Know About the Gravity Bridge Chain”
Compiled by: Hu Tao, Chain Catcher
Gravity is a fundamental force of the universe that aligns all planets in orbits within the composable cosmos. Like gravity, Gravity Bridge aims to aggregate liquidity from the Ethereum ecosystem into the Cosmos ecosystem through a simple, trustless, and interoperable design.
Interoperability and authenticity are the spirit of Cosmos and the blockchain internet, and it is these very core value propositions that will drive the ecosystem into the Cosmos DeFi era through Gravity Bridge!
Gravity Bridge Milestones So Far
Gravity Bridge recently announced several exciting milestones:
- Within weeks of enabling Inter-Blockchain Communication (IBC) (the Cosmos interoperability standard), Gravity Bridge entered the top 15 Cosmos chains on mapofzones.com, with 32 channels open to different Cosmos blockchains
- The Cosmos NFT platform Stargaze is collaborating with Gravity Bridge to send NFTs from Ethereum to Cosmos
- The initial airdrop for ATOM stakers and the OSMO community pool helped start the distribution of GRAV (the native token of Gravity Bridge) to the community
- Gravity Grants propose to distribute GRAV tokens through governance to teams building bridge tools and other infrastructure beneficial to the Cosmos ecosystem
- Cosmos Hub and several other Cosmos chains (Stargaze, Nym, Comdex, CertiK, and Chihuahua) are connected to the Ethereum ecosystem
- You can now use ATOM with Ethereum DeFi
What is Gravity Bridge?
The Gravity Bridge blockchain is a trustless, neutral bridge between the Ethereum and Cosmos ecosystems. Built using the Cosmos SDK, it uses a set of validators to sign transactions instead of a multi-signature or permissioned participant set.
The neutrality here means that the entire focus of the Gravity community is to provide the most efficient and secure bridge possible, rather than DeFi applications on the native chain. This neutrality aggregates transaction volume from multiple blockchains and sources, thereby increasing efficiency and reducing costs. All control of the bridge is entirely handled by the Gravity Bridge validator set.
Best Features:
The Gravity Bridge protocol is an extremely simple cross-chain bridge design focused on providing better security by eliminating design complexity.
- Highly Decentralized: All funds are directly controlled by validators (currently 140)
- Secure and Anti-Censorship: Advanced penalties ensure that validators cannot sign or submit bridging messages without consensus agreement
- Built for Cosmos: Specifically designed for the Cosmos ecosystem, serving as a neutral platform with a permissionless front end
- Gas Efficiency: Rollup-style batch transactions can reduce individual user gas costs by up to 96%
- Fast and Reliable: A robust relay rewards system combined with reduced gas costs creates extremely fast and reliable transfers through a decentralized, self-funded relay community
How Gravity Bridge Works
Unlike using IBC with finality on Cosmos chains, Gravity Bridge transfers assets between EVM blockchains, such as Ethereum and ERC-20s, Polygon, etc. Gravity Bridge has two defined components:
1) Solidity contracts on Ethereum
2) Cosmos SDK modules on the Gravity Bridge blockchain
Gravity Bridge works similarly to how all cross-chain bridges operate: locking native tokens on one side of the bridge and minting wrapped tokens of that token on the other side. Users then use this wrapped token and return it to the bridge to redeem for native assets on another chain.
For bridges to and from Ethereum, the most critical component is the Solidity contract. It holds the native assets sent through the bridge.
Gravity.sol is the Solidity contract developed by the Althea team that holds funds for the Gravity Bridge on Ethereum. Compared to the popular trend of other bridge designs, Gravity.sol is compact and easy to review, with only 580 lines of code. It has been audited by three independent teams (Informal, Least Authority, and Code4rena) and is non-upgradable, meaning auditors found it cannot be tampered with by any malicious actors and does not contain any type of trusted party.
Deposits:
Depositing assets from Ethereum into Gravity Bridge is permissionless and censorship-resistant. Each validator proves every deposit event that occurs on Ethereum. When an event is proven by more than 2/3 of the validator set, wrapped tokens are minted. Validators must submit all proofs in order.
Withdrawals:
Gravity Bridge batches withdrawal transactions, placing multiple SendToEth messages into a single batch. This is similar to Rollups on Ethereum: executing many transactions in a single shared context is much more efficient than executing them individually.
This process provides a massive efficiency boost, reducing gas costs by 96%.
For example, if the sending cost of an ERC20 transaction is $20, transferring tokens from Gravity Bridge to Ethereum in a batch transaction only costs $4, which is distributed across all individual transactions in the batch, with users paying less than $1 in fees.
The second advantage of batching is anti-censorship, as the Gravity Bridge protocol itself defines the transactions for each batch and then requires validators to produce valid signatures. Validators cannot avoid signing specific transactions, nor can relayers avoid relaying them.
Penalties and Security:
To ensure that the Gravity Bridge blockchain consensus still controls the bridge and its held assets, the Gravity Bridge protocol has established several rules:
- The protocol generates which messages validators should sign next
- After submitting signatures, they are verified as part of the consensus, and if validators do not sign the correct messages, they will be rejected
- If validators do not produce the correct signatures during the penalty period, they will be penalized and kicked out of the Gravity Bridge validator set (removing them from the bridge's Ethereum side as well)
- Anyone can slash a validator by submitting signature evidence through non-protocol messages
The evidence-based slashing of Gravity Bridge signatures makes it difficult for validators to collude to steal funds from the bridge. In doing so, they risk being slashed by any defector while trying to gather the required signatures.
How to Use Gravity Bridge
Gravity Bridge has a permissionless front end, and multiple teams have built user interfaces for sending assets to Cosmos or sending Cosmos assets to Ethereum. You can currently use the bridge to send between the Cosmos and EVM ecosystems:
If you want to get started with Gravity, you can find easy-to-use instructions here:
Tutorial: Sending Gravity Bridge Tokens (Gravitons) to Osmosis via IBC
Tutorial Documentation: Bridging Tokens and Using Gravity Bridge
Proposals to support as many assets as possible are underway, and the Cosmos Gravity Bridge already has some great projects integrated, including:
- ATOM
- HUAHUA
- NYM
- PERSISTENCE
- STARS
- COMDEX
The Team Behind Gravity Bridge
Contrary to popular belief, Gravity Bridge did not receive funding from Cosmos Hub proposals but was built and primarily funded by the Althea team with support from the Interchain Foundation, Peggy JV, and others, reflecting a long history as part of the Cosmos community, which is evident in the allocation of 9% of the initial token distribution to core Cosmos entities:
Core Ecosystem Total 9.000%
Interchain Foundation & Cosmos Hub Community Pool 154,000,000 7.000%
Peggy JV. 22,000,000 1.000%
Ignite (formerly Tendermint) 22,000,000 1.000%
GRAV Token Distribution
The initial genesis issuance outlines multiple funding and development sources for the bridge (development support and teams), including contributions from Althea, Peggy JV, and crowdfunding, arranged in order of value, as well as grants from the Interchain Foundation (ICF). The genesis also supports strong development teams and ecosystem consistency. Early Althea supporters and team allocations represent nearly 50 different entities and individuals who shared the blood, sweat, and tears needed over the years to build the talent and code that brought this bridge to life, and they will support the bridge in the future.
Gravity Bridge also exists as an open-source module, which has already benefited and will continue to benefit many other Cosmos chains in the ecosystem.
GRAV is minted and granted by the Gravity Foundation, with no prior sales of GRAV tokens or contributions from the ATOM community pool. 7% of the tokens are allocated to the Interchain Foundation to fund and coordinate part of the development of Gravity Bridge technology. The ICF has dedicated 110,000,000 GRAV tokens (5% of the total genesis) to the Cosmos Hub community pool.
Before cross-chain accounts are launched and sent to the Cosmos Hub community pool, the ICF will delegate the tokens to validators of the Cosmos Hub running on the Gravity chain. This will help ensure that the Gravity chain, consistent with ATOM, continues to invite Cosmos Hub validators to further participate in the path toward adopting cross-chain security for Gravity Bridge. If you are an ATOM holder wishing for Gravity Bridge Chain to adopt cross-chain security, consider delegating to Cosmos Hub validators.
All genesis tokens, except for validators, are subject to a 4-year lock-up schedule: locked for one year, with the remaining 3 years released incrementally.
Gravity Sustainability and Cosmos Growth
Unlike dApp or DEX chains, Gravity is infrastructure. Like aqueducts, sewers, roads, or bridges, they must last for years, reliably providing "normal operation" services. Therefore, when considering distribution, stakeholders should align with this usage over time, rather than just a "one-off" airdrop. Gravity Bridge started with an initial seed airdrop and proposes to distribute GRAV over time to users and teams building and maintaining the bridge.
To this end, an additional 50% of the genesis tokens have been allocated to the genesis community pool for distribution over the coming years to incentivize growth and support the maintenance and health of this critical infrastructure.
Once the community pool is fully distributed, the stakeholders of the bridge will be a decentralized pool of developers and bridge maintainers, ATOM and other Cosmos ecosystem holders, Cosmos core entities, and users of the bridge.
What’s Next?
- Initial seed airdrop: Completed
- Beta NFT support: Completed
- Initial Gravity grant proposal: Early March 2022
- Formation of Gravity growth: Early March 2022
- Mercury update March 2022
- Liquidity mining rewards for other DEXs (TBD)
- Additional EVM chain integrations (TBA)
The influx of stablecoins and liquidity into the Cosmos ecosystem will fuel the Cosmos DeFi fire. Open interoperability and new sources of liquidity will bring new participants to decentralized applications and the thriving Cosmos ecosystem of DeFi. The Cosmos DeFi era has arrived!
