Wrapped and bridged assets
A wrapped token is a cryptocurrency that represents an asset originally issued on a different blockchain. It exists because blockchains cannot natively understand each other's tokens. If you own Bitcoin on the Bitcoin blockchain and want to use it in a DeFi protocol on Ethereum, you cannot send it directly. You need a representation of that Bitcoin on Ethereum - a wrapped version - that can be redeemed for the original Bitcoin when you want it back.
That representation needs to be backed by something real. The entire wrapped asset ecosystem rests on this question: what actually guarantees that the token in your wallet can be exchanged for the original asset? The answer varies wildly depending on who holds the collateral, how the bridge software works, and what happens if something breaks.
This page maps the full territory. Each section below leads to a deeper spoke page that answers one question completely.
How wrapping physically works: lock and mint, burn and release
When you bridge an asset from one chain to another, something must happen to the original. It cannot be in two places at once. Two mechanisms handle this.
Lock and mint is the standard process. You send your Bitcoin to an address controlled by the bridge. That address locks the Bitcoin - it cannot be moved without a corresponding action on the destination chain. Once the bridge confirms the lock transaction is final (typically after a set number of block confirmations), it mints an equivalent number of wrapped tokens on the destination chain. The spoke page What lock and mint means for a wrapped token walks through exactly what happens to the original asset at each step, including the confirmation thresholds and what "locked" actually means at the smart-contract level.
Burn and release reverses the process. To get your original Bitcoin back, you send the wrapped tokens to the bridge contract on the destination chain, which destroys them - "burns" them so they can never be used again. The bridge then signals the source chain to release the original Bitcoin from its locked address. The spoke page How burn and release unwraps a bridged token back to the original explains what must happen on-chain for that conversion to complete, including the proof the bridge requires that the burn actually occurred.
Wrapped Ethereum, or WETH, is a special case worth understanding immediately. ETH is not ERC-20 compliant. Many DeFi protocols expect ERC-20 tokens, so Ethereum itself needs a wrapped version of its own native asset. WETH vs ETH what is the difference between wrapped and native Ether explains why Ethereum needs this wrapper, whether the two are interchangeable in practice, and why WETH trades at exactly the same value as ETH rather than at a premium or discount like many cross-chain wrapped tokens.
Who holds the collateral: custodian models and their failure modes
The safety of a wrapped token depends entirely on who controls the locked collateral. Three broad models exist.
Multi-signature custodian model. A group of entities - often companies, sometimes individuals - control a set of keys. To move the locked collateral, a threshold number of those keys must sign. For WBTC, BitGo holds the Bitcoin and a multi-signature arrangement involving BitGo, Kyber Network, and Ren (historically) authorises mints and redemptions. The spoke page How a multi-signature custodian model secures wrapped Bitcoin describes who actually holds the bitcoin backing WBTC and what technical and legal arrangements prevent them from simply taking it.
Smart-contract custodian model. No company or federation controls the keys. Instead, the locked collateral sits in a smart contract whose logic enforces the rules: only a valid burn-and-release proof can release funds. The spoke page What a smart contract custodian bridge is and how it holds collateral explains how a bridge contract can hold collateral without any human administrator, and what happens if the contract itself contains a bug.
Canonical wrapping vs third-party wrapping. The official team behind a blockchain or token can create a wrapped version, or an independent protocol can do it. For example, Arbitrum's canonical bridge wraps ETH as the "official" cross-chain ETH representation. But third-party bridges like Wormhole or Stargate also wrap ETH using their own contracts. The spoke page Canonical wrapping vs third party wrapped tokens what is the difference explains why the same asset has multiple wrapped versions on the same destination chain and which one is safer to hold under different threat models.
Liquidity-pool bridge vs lock and mint. Not all bridges lock your asset. Some use pre-funded pools: a pool on the source chain holds native tokens, a pool on the destination chain holds wrapped tokens, and the bridge simply swaps between them. The spoke page Liquidity pool bridge vs lock and mint which is faster and what you trade off explains why some bridges complete transfers in seconds (pool-based) while others take minutes or hours (lock-mint), and what you lose in return for that speed.
Choosing a wrapped Bitcoin: WBTC, tBTC, cbBTC, and the rest
Wrapped Bitcoin is the most common wrapped asset by market cap, and it is also the one with the most competing implementations. Each makes a different trust assumption.
WBTC is centralised. BitGo custodies the Bitcoin, and a multi-signature arrangement controls mints and redemptions. It is the most liquid and most widely accepted, but you are trusting a single company and its key-holder counterparties.
tBTC uses a threshold-signature scheme. A randomly selected group of signers holds the Bitcoin via a threshold ECDSA protocol - no single party can move the collateral. The spoke page WBTC vs tBTC vs cbBTC which wrapped Bitcoin fits your risk tolerance compares these models directly, including the newer cbBTC from Coinbase, and explains which wrapped Bitcoin aligns with different trust preferences.
renBTC was another decentralised option using RenVM darknodes, but the project was wound down after the Alameda/FTX collapse. It remains a cautionary example: a wrapped token can become permanently illiquid if the team abandons the bridge contracts.
Why bridge risk is not what it looks like
Many users assume that a bridge with high total value locked (TVL) is safe. This is false. TVL measures how much value is currently in the bridge's contracts, not how well those contracts are secured. The spoke page Why a bridge having high TVL does not mean it is safe to use explains why TVL is a misleading metric, using the example of the Wormhole exploit where $320 million was stolen from a bridge that had billions in TVL.
How a bridge smart contract exploit can drain wrapped token collateral covers the technical failure modes: infinite mint bugs that let an attacker create unbacked tokens, storage collision attacks that overwrite collateral balances, and signature replay attacks that drain the custodian contract. The spoke page walks through real exploit patterns from Ronin, Wormhole, and Multichain.
What causes a wrapped token to depeg from the underlying asset explains the market events that cause a wrapped token to trade below its collateral value: a bridge hack that makes redemptions uncertain, a custodian that suspends withdrawals, or a liquidity crunch that prevents arbitrageurs from restoring the peg. The spoke page covers the difference between temporary depegs caused by congestion and permanent depegs caused by insolvency.
The real cost of bridging: fees, delays, and hidden frictions
The fee displayed on a bridge UI is rarely the full cost. All the fees you pay when bridging assets between blockchains lists every charge: source-chain gas, destination-chain gas, the bridge minting fee, the redemption fee, relayer fees, liquidity-provider spreads, slippage on pool-based bridges, and the optional gas-on-destination surcharge. The spoke page includes real fee numbers for common bridges like Stargate, Across, and the Arbitrum canonical bridge.
Why optimistic rollup bridges make you wait 7 days to withdraw explains the dispute window that underpins optimistic bridge security. The spoke page covers why the delay exists, what happens if a dispute is raised, and whether there is a faster way to withdraw via third-party bridges that front liquidity.
Bridge rate limits and transfer caps why your transaction was blocked documents the specific error messages bridges return when they refuse a transfer. "Rate limit exceeded," "Maximum transfer exceeded," "Insufficient liquidity," "Bridge paused" - the spoke page explains what each means and what you can do about it.
When things go wrong: error states and recovery paths
Bridges fail in ways that leave funds in limbo. What to do when a bridge is paused and your funds are stuck mid-transfer covers the scenarios: the bridge operator halts the protocol due to a suspected exploit, a contract admin freezes the bridge after a governance attack, or a custodian suspends redemptions. The spoke page maps your options depending on whether your funds are still in the source-chain lock contract, in the relayer network, or on the destination chain awaiting claim.
What insufficient liquidity on a bridge means and how to fix it addresses the pool-based bridge failure where the destination pool cannot fulfil the requested swap. The spoke page explains how to check pool balances on DefiLlama's bridge dashboard, whether you can split the transfer across multiple bridges, and when you must simply wait for liquidity to be replenished.
Aggregation, diversification, and strategy
Using a bridge aggregator vs going direct to the bridge which is better compares the trade-offs of routing through Li.Fi, Bungee, or Squid versus using Stargate or Wormhole Portal directly. The spoke page includes cost comparisons and explains when the aggregator's additional protocol layer introduces its own failure risk.
Bridging a liquid staking token vs using a wrapped staked asset cross-chain addresses the choice between bridging an existing token like stETH across chains versus using a wrapped staked asset that is native to the destination chain. The spoke page explains the yield implications, the tax treatment differences, and why bridged staked assets sometimes carry additional depeg risk from the bridge itself.
Single-bridge exposure vs multi-bridge diversification is a decision that matters for anyone holding significant wrapped positions. Holding the same wrapped token from multiple bridges reduces the risk that a single bridge failure destroys your entire position - but it also means you must track which bridge each wrapped token came from, because Wrapped tokens from different bridges are not interchangeable. The spoke pages on canonical vs third-party wrapping and on WBTC vs tBTC vs cbBTC both reinforce this point.
The bottom line on wrapped assets
Every wrapped token is a promise. The promise might be enforced by a multi-signature arrangement with legal contracts, by a smart contract with mathematical guarantees, or by a federation of validators with economic incentives. None of these guarantees are absolute. Bridges have been hacked for hundreds of millions of dollars. Custodians have frozen withdrawals. Smart contracts have been upgraded to drain collateral.
The only question that matters for any wrapped asset you hold is: If the bridge or custodian fails tomorrow, can I still get my original asset back, and what would that process look like? The answer is different for WBTC than for tBTC, different for Arbitrum's canonical ETH bridge than for Stargate's pool-based ETH, and different for an asset bridged via Wormhole than for one bridged via LayerZero. The spoke pages linked throughout this pillar page answer that question for each specific case.
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