Trusted vs Trustless Bridge Designs: Which One Should You Use in 2025?

Imagine you want to send Bitcoin to an Ethereum-based DeFi app. You can’t do it directly. Bitcoin and Ethereum don’t talk to each other. That’s where blockchain bridges come in. They’re the invisible highways connecting isolated blockchains, letting you move assets like tokens, NFTs, or even data between them. But not all bridges are built the same. Some are like a bank vault guarded by a small team of people. Others are like a self-driving truck running on pre-programmed rules. One is faster. The other is safer. Choosing the wrong one could cost you thousands.

What’s the Difference Between Trusted and Trustless Bridges?

A trusted bridge relies on a small group of external validators - usually 5 to 20 entities - to confirm transactions. These validators hold your assets in escrow and sign off on transfers. Think of them as middlemen. Binance Bridge, Polygon POS Bridge, and Avalanche Bridge are all trusted designs. They’re fast, simple, and widely used. But if even one of those validators gets hacked, your money is at risk.

A trustless bridge skips the middlemen. It uses smart contracts and cryptographic proofs to verify transfers directly between blockchains. No central team controls the funds. Instead, the security comes from the underlying chains themselves - like Ethereum or Cosmos. Examples include Cosmos IBC, Polkadot’s Snowbridge, and Rainbow Bridge. These are slower and more complex, but they don’t depend on a few people to stay honest.

The key difference? Trusted bridges shift trust from code to people. Trustless bridges shift trust from people to code. Neither is perfect. One trades speed for control. The other trades convenience for security.

How Do Trusted Bridges Work - And Why They Got Hacked

Trusted bridges work by locking your asset on the source chain and issuing a wrapped version on the target chain. You send 1 ETH to a smart contract on Ethereum. A validator group confirms the deposit. Then, they sign a message to mint 1 wETH on Polygon. When you want it back, you burn the wETH, and they release your original ETH.

This system is efficient. Transfers take 2-5 minutes. Fees are low - often under $2. That’s why 68% of the $15.2 billion locked in bridges as of September 2024 runs through trusted designs. Major exchanges love them because they’re easy for retail users to understand.

But that simplicity is also their weakness. In March 2022, the Ronin Bridge lost $625 million. Attackers didn’t break the code. They compromised four of the nine validator nodes - and Sky Mavis, the company behind Ronin, controlled four of them. The bridge didn’t fail because of a bug. It failed because one company had too much control. The same thing happened with Harmony’s Horizon Bridge in October 2023 - $100 million stolen when validators were compromised.

Here’s the harsh truth: 87% of trusted bridges have more than half of their validator power controlled by just three entities. That’s not decentralization. That’s a single point of failure dressed up as a bridge.

How Trustless Bridges Work - And Why They’re Still Not Perfect

Trustless bridges don’t use external validators. Instead, they rely on two main methods:

• Light client bridges (like Cosmos IBC): One chain runs a lightweight version of the other chain’s blockchain state. It verifies transactions using cryptographic proofs, like checking a notarized document without calling the notary.
• Liquidity networks (like Connext or Across): These use pooled liquidity and atomic swaps. You send tokens to a pool on Chain A. Someone else receives equivalent tokens from a pool on Chain B. No central custodian holds your assets.

These designs are more secure because they inherit the security of the source and target chains. If Ethereum is secure, then a bridge built on top of it inherits that security - assuming the code is flawless.

But code isn’t flawless. In February 2022, Wormhole, a trustless bridge, lost $326 million. A single smart contract bug let attackers mint unlimited ETH on Solana. No validators were hacked. The code just had a flaw. That’s the trade-off: trustless bridges remove custodial risk but add smart contract risk.

Dr. Gavin Birch from Electric Capital put it simply: “Trustless bridges aren’t truly trustless - they shift trust from centralized entities to the underlying blockchain’s security model and the correctness of the bridge’s smart contracts.”

Speed, Cost, and Usability: Real-World Trade-Offs

Here’s how trusted and trustless bridges compare in practice:

For most people sending $100 to try a new DeFi app, a trusted bridge is fine. Fast, cheap, simple. But if you’re moving $50,000? The data says 63% of users prefer trustless bridges for amounts over $10,000. They’d rather wait 15 minutes than risk losing it all.

Who Uses Which Bridge - And Why

Usage patterns tell a clear story:

• Retail users (under $5,000): 62% use trusted bridges. They don’t care about decentralization. They want it to work now. Binance, Coinbase, and MetaMask integrate trusted bridges because they’re easy to implement and explain.
• Institutional users (over $50,000): 47% use trustless bridges. Hedge funds, DAOs, and DeFi protocols prioritize security over speed. They know the history of bridge hacks. They’re willing to wait.
• Developers: Building on a trusted bridge takes 15-25 hours. Building on a trustless bridge? 40-60 hours. That’s why most DeFi apps now offer both - trusted for small swaps, trustless for core liquidity pools.

Enterprise adoption is split. Banks and regulated institutions prefer trusted bridges because they can comply with anti-money laundering rules - they know who’s running the validators. Decentralized apps, on the other hand, avoid trusted bridges entirely. Why? Because they’re built on the idea that no one should be able to freeze your assets.

The Future: Hybrid Bridges and Trust-Minimized Designs

The industry is evolving. The old binary - trusted vs trustless - is fading. New bridges like LayerZero v2 and Chainlink’s CCIP are blending both models. They use decentralized oracles, multiple relayers, and economic incentives to reduce trust assumptions without sacrificing speed.

These are called trust-minimized bridges. They don’t eliminate trust. They minimize it. They use 10+ independent nodes instead of 5. They require multiple signatures. They add fraud proofs and time delays to catch attacks.

And the market is responding. The number of active bridges dropped from 127 in early 2023 to 89 by late 2024. Weak, centralized bridges are dying. Users are voting with their wallets. The survivors are the ones that prioritize security without making users suffer.

As Vitalik Buterin said in 2023: “For high-value transfers, users should prefer bridges with minimal trust assumptions, even if they’re slower.” That’s not just a suggestion - it’s becoming industry doctrine.

What Should You Do?

Here’s a simple rule to follow in 2025:

• Under $5,000? Use a trusted bridge if it’s from a major exchange (Binance, Coinbase, OKX). It’s fast and you’ll get help if something goes wrong.
• $5,000-$50,000? Use a trustless bridge - especially if it’s built on Ethereum, Cosmos, or Polygon’s native chain. Look for bridges with open-source code and public audits.
• Over $50,000? Only use bridges with multiple independent relayers, fraud proofs, and at least two independent audits. Avoid anything with a small validator set. If you don’t understand how it works, don’t use it.

Always check the bridge’s history. Has it been hacked? Did the team respond? Was the code audited by a reputable firm like CertiK or OpenZeppelin? If the answer is no - walk away.

There’s no perfect bridge. But there are smarter choices. The biggest risk isn’t slow transfers. It’s losing your life savings because you picked convenience over security.