Bridges between blockchains: what is it and how does it work?

Every blockchain differs in terms of its rules and consensus mechanisms and develops in a closed environment. As a result, there is no natural interaction and free transfer of tokens between blockchains. The exchange of data and tokens between blockchains is made possible by bridges that connect them.

Activity on trustless bridges is typically managed in a similar way to the blockchain itself where a set of validators need to reach consensus over transactions. Validators are incentivized to ensure the integrity of bridge activity through rewards and penalties. Examples of trustless bridges include the Arbitrum Bridge and the Polygon Bridge. Non-custodial bridges operate in a decentralized manner, relying on smart contracts to manage the crypto locking and minting processes, removing the need to trust a bridge operator. Trustless bridges are much more complicated on a technical level than some custodial bridges. This type of bridge can include many ins and outs across the blockchains they operate.

Exploits have become so common in the cryptocurrency industry that a significant hack occurs monthly on average. According to Bloomberg, the USD equivalent lost in bridge hacks in 2022 exceeds $1 billion. The cryptocurrency industry is constantly evolving as a response to growing public adoption. Public adoption and usage have caused congestion on leading blockchains in the past.

A blockchain bridge facilitates the conversion of one native asset from one blockchain to its equivalent on another blockchain. There are different routes to transferring assets from one chain to another. While bridges are a prominent option, crypto exchanges also offer cross-chain functionality. They must assume that the centralized entity will never steal their assets and protect their funds from attackers. Some blockchain bridges, such as “Cross-Chain Bridge” and Synapse Protocol, adopt different approaches. For instance, there are liquidity pools for WETH on BNB Chain, Polygon, and so on.

Trustless bridges may be vulnerable to majority attacks, particularly if the validator set is made up of a smaller group. Attackers will also seek out bugs or insecurities in the bridge smart contracts (which can be particularly complex) to find a way of draining funds. Since you need smart contracts on both blockchains to build a bridge, there are more attack vectors and points-of-failures within their code. The development of the blockchain industry is driven by constant innovations. There are the pioneer protocols like the Bitcoin and Ethereum networks, followed by a myriad of alternative layer 1 and layer 2 blockchains. To use the Binance Bridge, for example, you will first select the chain you’d like to bridge from and specify the amount.

• Let’s explore the different types of blockchain bridges to understand their operations better.
• The most seamless bridges among sub-chains (Ethereum-Arbitrum) or compatible chains (BnB Chain, Avalanche, Pulsechain, Polygon, Ethereum).
• An interoperable blockchain sector is critical to the industry’s future success.
• As such, trustless bridges have faced many different attacks and exploits in recent years.
• If you use a bridge to send one Solana coin to an Ethereum wallet, that wallet will receive a token that has been “wrapped” by the bridge – converted to a token based on the target blockchain.

This allows the attacker to reenter and execute the function multiple times in a single transaction. In the context of bridges, this can lead to funds being illicitly withdrawn multiple times, causing substantial losses. https://www.xcritical.in/ The infamous 2016 DAO attack on Ethereum, which resulted in the theft of 3.6 million Ether, was a type of reentrancy attack. Whatever benefits bridges bring to blockchain have so far come at a very steep price.

A specific blockchain bridge could not support and work with every blockchain network or asset in the decentralized applications industry. In addition, you can find a list of blockchain bridges focused on addressing unique user requirements. Here is an outline of the notable blockchain bridge variants you can use for transferring assets and information between blockchain networks. Blockchain bridges offer unique features and adaptations that contribute to the growth of blockchain technology. They allow fluid switching between blockchain networks, benefiting investors, developers, and users. Blockchain bridges provide opportunities for user growth, asset production, transfer, and scalability.

Even at that, the transaction fees of most bridges are ridiculously low compared to what exchanges would have charged. Every innovation bears its inherent risk, and crypto bridges are no exception. Most bridges using this method often have staking and farming programs where users can lock their assets into the pool for periodic rewards. A high-frequency trading firm called Jump Trading covered the losses to bail out the protocol.

So the 21 validators halted the network briefly until the issue was solved. There’s no standard way of building one, among other reasons, because each network is a different ecosystem/ consensus model/ language. So even if we can design around those risks, we might not discover them until millions of tokens are again stolen. If you search for the most expensive DeFi attacks of all time, bridges make most of the list. Delving deeper into the Wormhole saga, insights from Elliptic, a blockchain analysis firm, highlighted a flaw that let the attacker produce 120,000-wrapped Ethereum without staking actual ETH. Capitalizing on this loophole, the attacker swiftly liquidated the undeserved WETH.

User X is in a quandary if they wish to pay user Y for something, but Ethereum only takes ETH. Due to the interoperability provided by bridging solutions, they can still buy ETH or convert part of their BTC into ETH. It’s a disadvantage compared to regular what is a blockchain bridge and how it works fiat transferring/exchanging since fiat currencies and many banks and financial institutions can utilize credit cards. Cross-chain bridges enable many innovative processes, but security concerns surround them, as these apps have experienced hacking losses.

Interestingly, an overview of the different variants of a blockchain bridge could shed further light on their work. Just like blockchain networks featuring distinctive defining parameters, blockchain bridges also have different traits. On the other hand, platforms that rely purely on smart contracts and algorithms to store custody assets are referred to as trustless bridges. Blockchain bridges largely depend on smart contracts to facilitate seamless transactions between different networks. Simple mistakes in the contract code can inadvertently introduce vulnerabilities, making them susceptible to exploitation.

The code used in ChainPort’s smart contracts is all original and not publicly viewable. Not revealing the code behind the bridge minimizes potential attack vectors. Hackers have focused on blockchain bridges as they store a large amount of value in the form of tokens. As per CoinTelegraph, over $2.5 billion has been stolen from blockchain bridges in the past two years. An atomic swap is a technique where two different cryptocurrencies can be exchanged directly from one party to another.

For instance, the Parity Multisig Wallet Bug in 2017 resulted from a simple contract bug, leading to the freezing of 513,774.16 Ethereum, which was worth hundreds of millions of dollars. It is essential to recognize their need to understand how blockchain bridges work. Blockchain networks exist as separate communities with their economies, limiting their interactions.