AN INTRODUCTION TO THE VARIOUS TYPES OF CROSS-CHAIN BRIDGE SOLUTIONS

Last updated: June 20, 2025, 01:08 | Written by: Jed McCaleb

Imagine a world where different blockchains, each a unique ecosystem, can communicate and transact with each other seamlessly.This is the promise of cross-chain bridge solutions, a critical piece of infrastructure in the evolving landscape of Web3. An introduction to the various types of cross-chain bridge solutions: Cointelegraph offers a different approach to blockchain bridges, covering three technical types such as the notary model, hashA cross-chain bridge acts as a connector, enabling the transfer of assets and data between otherwise isolated blockchain networks. Cross-chain Interoperability Solutions. Cross-chain interoperability solutions are networks that act as an interoperability layer to facilitate cross-chain communications for blockchain applications. They allow the transfer of assets, messages, and contract calls to and from any blockchain supported by the network.This interoperability unlocks a wealth of possibilities, from enhanced liquidity and expanded DeFi applications to entirely new types of decentralized applications (dApps).But with a variety of approaches available, understanding the different types of bridges, their mechanisms, and their associated risks is crucial for anyone navigating the multi-chain future.Since its inception in 2015, cross-chain technology solves the problem of blockchain interoperability and enables users to communicate and share data across multiple networks.This article will delve into the fascinating world of cross-chain bridges, exploring their functionality, different types, and the challenges they face in creating a truly interconnected blockchain world.We will also explore practical examples of how these bridges are being utilized today and offer insights into the potential future of this transformative technology.

What are Cross-Chain Bridges and Why Do We Need Them?

At their core, cross-chain bridges are infrastructure elements designed to facilitate communication and value transfer between distinct blockchain networks. A blockchain bridge, also known as a crypto bridge or cross-chain bridge, is a protocol that connects two different blockchains. It enables users to transfer cryptocurrency from one chain to another. You can also transfer assets to another blockchain using a crypto exchange, such as selling bitcoin (BTC) for ether (ETH). However, depending onBlockchains, by nature, operate as isolated silos. Cross-chain bridges are the connective tissue that allow different blockchains to securely share data and assets. At their core, these bridges employ a messaging system that permits blockchains to pass information to each other in a verifiable way.Without bridges, transferring assets like Bitcoin or Ethereum between chains would be impossible without relying on centralized exchanges.These bridges essentially create pathways that allow assets and data to flow freely, creating a more unified and versatile blockchain environment. Cross-chain bridge transfers are executed by third party relayers or fillers, who use their own capital on the destination chain to quickly send tokens to bridge users on their desired chain. These fillers compete to execute bridge transfer requests, and this competition drives down fees and speeds up transactions.They're the connective tissue that allows different blockchains to securely share data and assets, which is critical for DeFi and other blockchain applications.

The need for cross-chain bridges stems from the inherent limitations of isolated blockchains. Here, we will present three technical solutions for cross-chain transactions, analyze their characteristics and discuss their potential risks. These three solutions are the notaryConsider these points:

Interoperability: Bridges break down the walls between blockchains, enabling seamless interaction between different ecosystems.
Liquidity: By allowing assets to move freely, bridges consolidate liquidity across multiple chains, reducing slippage and improving trading efficiency.
Scalability: Bridges can leverage the unique strengths of different blockchains, allowing users to access faster and cheaper transactions on networks optimized for specific tasks.
Innovation: Cross-chain dApps can combine the features of multiple blockchains, creating entirely new functionalities and use cases.

The Building Blocks: How Cross-Chain Bridges Work

While the specific implementation of cross-chain bridges can vary, the underlying principle remains the same: to establish a secure and verifiable channel for transferring information and value between blockchains. DEX Bridge Aggregators: Uniting the Crypto Ecosystem. DEX Bridge aggregators combine the benefits of DEX and bridge services, enabling seamless cross chain swaps and enhanced trading opportunities. Jumper.Exchange (Li.Fi) Jumper Exchange is a multi-chain bridging and swapping platform powered by Li.fi, with support for 17 networks.Generally, this involves these steps:

Initiation: A user initiates a transaction on the source chain, specifying the asset to be transferred and the destination chain.
Locking/Burning: The asset is either locked in a smart contract on the source chain or burned (destroyed) on the source chain. Blockchain cross-chain bridges can be categorized into two main types: Trusted Bridges and Trustless Bridges. Each type differs in its trust process, with its own advantages and disadvantages. 1.Trusted Bridges. Trusted Bridges are controlled by centralized entities or operators to achieve interoperability.This action is a critical security measure to ensure that the asset is not double-spent.
Verification: The bridge verifies that the locking or burning event has occurred on the source chain.This verification process often involves a network of validators or oracles.
Minting/Releasing: On the destination chain, a corresponding amount of the asset is either minted (created) or released from a locked state.This creates a representation of the original asset on the new chain.
Transfer: Third party relayers or fillers will use their own capital on the destination chain to quickly send tokens to bridge users on their desired chain. Cross-chain also emphasizes decentralization, reducing reliance on a single intermediary, thereby lowering transaction costs and improving efficiency . Moreover, the design flexibility of cross-chain enables it to adapt to various blockchain characteristics and requirements, supporting a diverse range of business scenarios and applications .These fillers compete to execute bridge transfer requests, and this competition drives down fees and speeds up transactions.

Mechanisms Propelling Cross-Chain Bridges

Cross-chain bridges employ different mechanisms to achieve the steps mentioned above.Here are some of the most common:

Lock and Mint: This is the most prevalent mechanism.A user locks tokens in a smart contract on the source chain, and wrapped versions of those locked tokens are minted as a form of IOU on the destination chain.
Burn and Mint: This mechanism is similar to lock and mint, but instead of locking the tokens, they are burned (destroyed) on the source chain. In addition to wrapping tokens, cross-chain bridges can also use liquidity pools as a bridging mechanism. In these types of blockchain bridges, crypto assets are deposited in liquidity pools, enabling liquidity providers to earn rewards while allowing users to bridge assets from one chain to another (and back). Types of Blockchain BridgesThis guarantees that the same tokens are not present on both the source and destination chains.
Liquidity Pools: Crypto assets are deposited in liquidity pools, enabling liquidity providers to earn rewards while allowing users to bridge assets from one chain to another (and back).

Exploring the Landscape: Types of Cross-Chain Bridges

Cross-chain bridges can be categorized based on several factors, including their trust model, underlying technology, and the types of assets they support.However, one of the most common classifications is based on their level of trust:

Trusted (Centralized) Bridges

Trusted bridges rely on a central entity or a group of trusted validators to facilitate cross-chain transfers.These bridges are often faster and more efficient than their trustless counterparts, but they also introduce a single point of failure.If the trusted entity is compromised, the entire bridge can be vulnerable.

Characteristics of Trusted Bridges:

Centralized Control: Operated by a single entity or a limited number of validators.
Higher Speed: Transactions are typically faster due to the centralized nature.
Lower Cost: Transaction fees are often lower compared to trustless bridges.
Security Risks: Vulnerable to hacks and malicious actors targeting the central authority.

Trustless (Decentralized) Bridges

Trustless bridges, also known as decentralized bridges, aim to minimize reliance on trusted intermediaries by utilizing cryptographic techniques, smart contracts, and decentralized validator networks. Methodology. Research on blockchain interoperability is expanding rapidly in both industry and academia.Terms such as cross-chain bridge, cross-chain routing, and cross-chain communication protocol are increasingly prevalent in various documents and discussions.These bridges are generally more secure than trusted bridges, but they also tend to be slower and more expensive.

Characteristics of Trustless Bridges:

Decentralized Validation: Rely on a network of validators to verify transactions.
Enhanced Security: Less vulnerable to attacks due to the decentralized nature.
Slower Speed: Transactions typically take longer due to the need for decentralized consensus.
Higher Cost: Transaction fees are often higher to compensate validators.

Hybrid Bridges

As the name suggests, hybrid bridges combine elements of both trusted and trustless approaches.They may utilize a mix of centralized and decentralized components to achieve a balance between speed, cost, and security.

Deep Dive: Technical Cross-Chain Bridge Solutions

Beyond the high-level classifications of trusted and trustless, understanding the underlying technical approaches is essential. It establishes lightweight cross-chain bridges, reducing cross-chain transaction costs and delays. Across s technical characteristic lies in its optimization for Layer 2 networks. It fully utilizes Layer 2 advantages, such as higher transaction throughput and lower transaction fees, providing users with better cross-chain experiences.Here are some of the technical solutions used in cross-chain bridges:

The Notary Model

The notary model is a relatively simple approach where a group of trusted notaries monitors activity on both the source and destination chains. Cross-chain bridges are propelled by three primary kinds of mechanisms: Lock and mint- A user secures tokens in a smart contract on the source chain, and then wrapped versions of those locked tokens are minted as a form of IOU on the destination chain.When a transaction is initiated, the notaries verify the transaction on the source chain and then collectively sign a message authorizing the corresponding transaction on the destination chain. Cross-chain bridges allow assets and data to flow seamlessly between these networks, creating a unified ecosystem and broadening the use cases for decentralized applications (dApps). Types of Cross-Chain Bridges. Several cross-chain bridge solutions have emerged to address the needs of different blockchain ecosystems. Some notable options include:This model relies heavily on the trustworthiness of the notaries.

Hash Time-Locked Contracts (HTLCs)

HTLCs are a cryptographic technique that enables conditional payments across different blockchains. What are Cross-Chain Bridges and Their Types? Software programs known as cross-chain bridges make it possible for transactions to take place between different blockchains. Cross-chain bridges are crucial components of any transaction that involves the transfer of Bitcoin, NFTs, and Decentralized Finance (DeFi) within blockchain networks. AThey involve creating contracts on both the source and destination chains that are locked with a secret hash. Section 2 introduces the working principle of cross-chain bridges and provides an overview of different types of cross-chain bridges. The section also features a summary of various cross-chain bridge projects, categorizing them as centralized, decentralized, or hybrid, and lists their respective security features.The recipient can only claim the funds if they provide the secret that unlocks both contracts. Blockchain bridges. Cross-chain bridges connect two or more blockchain networks, allowing them to interact and transfer assets. They can be implemented through various methods, such as pegged assets (where a token on one blockchain represents an asset on another) or cross-chain oracles that provide data and validation across blockchains.This ensures that the transaction is atomic, meaning that either both parties receive their funds, or neither does.The limitation of HTLCs is that both chains must support the same hash algorithm.

Relay Chains

Relay chains operate as a central hub that connects multiple blockchains. This guide explores how blockchains have evolved into a cross-chain world, the different types of blockchain networks, and the ongoing challenges and risks associated with blockchain interoperability.Each blockchain connects to the relay chain, which then facilitates cross-chain communication and asset transfers. Vulnerabilities in cross-chain bridges and smart contracts. Example: The $610 million Poly Network hack highlighted the risks of cross-chain operations. Scalability Issues. High transaction volumes can strain cross-chain networks. Standardization. Lack of universal standards complicates interoperability efforts. ComplexityRelay chains often use a consensus mechanism to validate transactions and ensure the security of the network. This is why the cross-chain bridge has become one of the most important infrastructures in the Web3 world today. What is a Cross-Chain Bridge? Unlocking the Asset Transfer Channel Between Blockchains. A Cross-Chain Bridge is specifically designed to address the issue of lack of communication between chains. Its purpose is to create a bridgePolkadot and Cosmos are prime examples of relay chain-based interoperability solutions.

Benefits of Cross-Chain Bridges

The proliferation of cross-chain bridges brings numerous advantages to the blockchain ecosystem:

Enhanced Interoperability: Allows different blockchains to communicate and interact, breaking down silos.
Increased Liquidity: Enables the movement of assets across chains, consolidating liquidity and improving trading efficiency.
Scalability Solutions: Allows users to leverage the strengths of different chains for specific tasks, potentially improving scalability and reducing transaction costs.
Access to New Markets: Opens up access to new markets and investment opportunities by allowing users to easily move assets between different ecosystems.
Innovation in dApps: Enables the creation of cross-chain dApps that combine functionalities from multiple blockchains.
Reduced reliance on centralized exchanges: Offers a decentralized alternative for moving assets between different blockchains.

Risks and Vulnerabilities Associated with Cross-Chain Bridges

Despite the many benefits, cross-chain bridges also introduce new risks and vulnerabilities, especially in their current stage of development. Cross-chain bridges enable the transfer of assets or data between different blockchain networks, creating interoperability and connectivity. The specific workings of cross-chain bridges can vary depending on the implementation, and can include lock mint, burn mint or other mechanisms.The security of bridges has become a major concern, as they have become attractive targets for malicious actors. Risks and vulnerabilities in crosschain bridges. While cross-chain bridges offer significant benefits, they also introduce new risks, especially at the nascent stages of development. Two high-profile incidents highlight these dangers:Some of the major risks include:

Smart Contract Vulnerabilities: Bugs in the smart contracts that govern the bridge can be exploited to steal funds.
Validator Attacks: If a significant number of validators in a decentralized bridge are compromised, they can collude to steal assets.
Key Management Risks: If the private keys used to manage the bridge are compromised, attackers can gain control of the assets.
Economic Exploits: Flaws in the economic incentives of the bridge can be exploited to drain funds.
Regulatory Uncertainty: The regulatory landscape surrounding cross-chain bridges is still evolving, which could create legal and compliance risks.

The $610 million Poly Network hack highlighted the risks of cross-chain operations.It's a stark reminder that the nascent stages of development in the cross-chain space are inherently vulnerable.Therefore, it's essential to carefully evaluate the security measures implemented by each bridge before using it.

Practical Examples of Cross-Chain Bridges in Action

Numerous cross-chain bridge projects are currently active, each with its own unique design and functionality. Cross-chain dApps have unified logic across smart contracts deployed on different blockchains. Cross-chain dApps that leverage cross-chain messaging protocols can be limited in scope; token bridges, for example, only exist to enable tokens on a source blockchain to be transferred to a destination blockchain.Here are a few notable examples:

Across Protocol: Optimizes for Layer 2 networks, leveraging their higher transaction throughput and lower fees.
Jumper.Exchange (Li.Fi): A multi-chain bridging and swapping platform supporting 17 networks.

These examples demonstrate the diverse range of applications for cross-chain bridges, from simple token transfers to complex DeFi interactions.

The Future of Cross-Chain Bridges: What Lies Ahead?

The future of cross-chain bridges is bright, with ongoing research and development focused on improving security, efficiency, and scalability.We can expect to see more sophisticated bridge designs, improved validator networks, and greater adoption of cross-chain dApps. The concept of cross-chain was first proposed by the Tendermint team in 2025. On Septem, Vitalik Buterin, the founder of Ethereum, published an article Chain Interoperability at the R3CEV conference, which raised the issue of blockchain interoperability, and made the concept of cross-chain officially enter the researchers' vision [3].Ultimately, the goal is to create a truly interconnected blockchain ecosystem where assets and data can flow seamlessly between different networks.However, standardization remains a hurdle.The lack of universal standards complicates interoperability efforts and further exposes potential vulnerabilities.

DEX Bridge Aggregators: A Promising Development

One exciting development is the emergence of DEX Bridge aggregators, which combine the benefits of decentralized exchanges (DEXs) and bridges. Cross-chain bridges work by allowing information to be transferred from one blockchain to another. For this, they feature distinct programming and protocols, often leveraging the power of smart contracts to ensure security, transparency, and permissionlessness.These aggregators enable seamless cross-chain swaps, allowing users to trade tokens directly between different blockchains without the need for centralized intermediaries.This enhances trading opportunities and provides a more user-friendly experience.

Conclusion: Embracing the Interconnected Blockchain Future

Cross-chain bridges are a fundamental building block of the future blockchain ecosystem.They unlock interoperability, enhance liquidity, and enable new possibilities for decentralized applications.While challenges remain, the ongoing development of more secure, efficient, and user-friendly bridges promises to create a truly interconnected and versatile blockchain world. Crosschain bridges are self-explanatory they allow you to bridge your assets across blockchains. Bridges play a central role in interoperability, allowing for the transfer of tokens and data between networks. They enhance liquidity and enable crosschain interactions while offering different security models tailored to varying network needs.Understanding the different types of bridge solutions, their underlying mechanisms, and their associated risks is crucial for anyone looking to participate in this exciting future. However, the introduction of cross-chain technology solves these problems by facilitating blockchain interoperability and enabling users to communicate and share data. The cross-chain protocol facilitates interoperability between different blockchain networks and enables the exchange of data between several networks.As you explore the world of Web3, remember that cross-chain bridges are the pathways that connect different ecosystems, paving the way for a more unified and collaborative blockchain landscape.Consider the security of the bridge carefully and always exercise caution when transferring assets across chains.The evolution of cross-chain bridge solutions is still underway, and its continued development is paramount for realizing the full potential of a decentralized, interconnected future.