Overview
The Avalanche Bridge (AB), developed by Ava Labs, facilitates the secure and efficient transfer of assets between the Avalanche and Ethereum networks, as well as Bitcoin. Launched in July 2021, AB replaced the previous Avalanche-Ethereum Bridge (AEB), offering reduced fees, stronger security, and faster transaction finality. The bridge supports transfers of ERC-20 tokens and Bitcoin (BTC) between their home chains and Avalanche, enhancing interoperability and flexibility for users.
One of the easiest ways to use the Avalanche bridge is through https://core.app/en/bridge/
How It Works
Ethereum to Avalanche
Users send ERC-20 tokens to the Avalanche Bridge address on Ethereum. The bridge nodes, utilizing a combination of smart contracts and Intel SGX (Software Guard Extensions) technology, validate the transaction. Once validated, wrapped tokens (e.g., USDC.e) are minted on Avalanche and sent to the user’s address on the Avalanche C-Chain.
Avalanche to Ethereum
Users initiate the process by burning the wrapped tokens on Avalanche. Once this transaction is confirmed, the equivalent ERC-20 tokens are unlocked on Ethereum and sent to the user’s Ethereum address.
Bitcoin to Avalanche
Users send BTC to a bridge-controlled address using the Core Wallet interface. After confirmation, equivalent BTC.b tokens are minted on Avalanche. For transfers back to Bitcoin, BTC.b tokens are burned on Avalanche, and the equivalent amount of Bitcoin is sent to the user’s Bitcoin address.
Key Features
Transaction Speed
Transfers typically take 10–15 minutes due to Ethereum’s finality constraints, while the Avalanche side processes transactions in a few seconds.
Fees
- Ethereum to Avalanche: A fee of $3 in the ERC-20 token being moved.
- Avalanche to Ethereum: A fee of $20 plus the estimated Ethereum gas fee.
- Bitcoin to Avalanche: A fee of $3 worth of Bitcoin.
- Avalanche to Bitcoin: A fee of $20 plus the Bitcoin transaction fee.
AVAX Airdrop
For first-time users, a small amount of AVAX is airdropped for transactions larger than $75 to cover initial transaction fees on Avalanche.
Security
Security Model
The Avalanche Bridge employs a robust security model that includes:
- Smart Contract Audits: Regular third-party audits to ensure the integrity of the bridge.
- Intel SGX Enclave: Utilizes secret sharing to secure private keys, ensuring that no funds can be released without corresponding transfers of coins.
- Reputation: Wardens managing the bridge are financially and reputationally incentivized to act in good faith.
Role of AVAX Token
To facilitate transactions on Avalanche, the AVAX token is required. For transfers over $75, a small amount of AVAX is airdropped to users’ wallets to enable initial transactions.
Limitations and Risks
Wallet Support
Only transactions to the same wallet address on the other chain are supported. Sending tokens directly to the bridge’s wallet can result in loss of funds. Smart contract wallets like Ambire or Gnosis Safe are not supported.
Trusted Design
The security relies on the reputation and integrity of the bridge nodes. Any collusion or compromise among the bridge nodes could pose significant risks to the assets being transferred.
The Avalanche Bridge represents a significant advancement in cross-chain interoperability, offering users a secure, efficient, and cost-effective solution for transferring assets between Avalanche, Ethereum, and Bitcoin.
