Bitcoin isn’t the only blockchain—there are thousands—and they aren’t compatible. It’s not possible, for instance, to directly send Bitcoin to an Ethereum address. Instead, crypto users rely on a workaround called crypto bridges.
When you want to transfer crypto assets from one chain, like Ethereum, to another chain, such as Solana, crypto bridges will hold your coins from the first chain in digital vaults and create synthetic tokens for use on the second chain. This amounts to an escrow system of sorts. Of course, users can’t use the tokens in the vault and the synthetic tokens at the same time.
Bridges support different assets and chains. While Hop Exchange supports a handful of chains compatible with the Ethereum network, like Polygon and Gnosis, Connext supports technically diverse chains, like Cronos and Moonriver. Other popular bridges include Synapse, Across, cBridge, and Anyswap.
USDC and USDT, two major stablecoins pegged to the price of the U.S. dollar, are the most common assets to bridge across blockchains.
As the Bitcoin blockchain does not support decentralized finance protocols, developers built bridges that allow for Bitcoin to be bridged to smart contract chains like Ethereum.
You can deploy synthetic tokens like Wrapped Bitcoin (WBTC) or Ren Bitcoin (REN) in DeFi protocols to borrow, lend or earn interest, or trade. RenBridge is also popular for the Bitcoin-Ethereum route.
Crypto bridges are victims of some of the industry’s biggest heists. The blockchain game Axie Infinity fell prey to a $626 million hack related to a bridge between Ethereum and its Ronin sidechain in March 2022. An attacker siphoned $611 million out of Poly Network, which operates in multiple chains, in October 2021. And in February 2022, Solana’s bridge Wormhole lost $326 million.
Ethereum inventor Vitalik Buterin warned in 2022 that bridge technology is fundamentally insecure and urged people to be cautious in using it.
Go deeper:
Security Stack-Up: How Bridges Compare—Jump Crypto
Bridge TVL Rankings—DeFi Llama
See also:
What are blockchains?
What are layers in blockchain?
What is Ethereum?
Try it:
MetaMask—a top crypto wallet, where you can make in-app crypto purchases
Hop Exchange—send crypto from one chain to another using a crypto wallet