Different blockchains don't talk to each other. Bitcoin has no idea Ethereum exists. ETH doesn't natively exist on Solana.

Wrapped tokens solve this. Lock the original asset somewhere. Mint an equivalent token on the destination chain. That token represents the original 1:1.

WBTC is Bitcoin on Ethereum. Same value as BTC. Usable in Ethereum DeFi. Actual BTC sitting in reserve somewhere backing every WBTC in existence.

Simple concept. Significant trust assumptions buried inside it.

How Wrapping Actually Works

Two versions. Centralized and decentralized.

Centralized wrapping. Send BTC to a custodian. Custodian mints equivalent WBTC on Ethereum. Want your BTC back, burn the WBTC, custodian releases the BTC. Custodian holds the real asset the entire time. You're trusting that company completely.

Decentralized wrapping. Smart contract locks the original asset. Mints the wrapped version. Burn the wrapped token, smart contract releases the original. No company in the middle. Smart contract risk instead of custodian risk. Different trust assumption, not no trust assumption.

Bridges work on the same principle. Bridge ETH from Ethereum to Arbitrum. Your ETH gets locked on Ethereum. Wrapped representation minted on Arbitrum. Bridge back and the process reverses.

WBTC: Bitcoin in DeFi

Most liquid wrapped asset in existence. Billions in WBTC sitting in Ethereum DeFi protocols. Used as collateral on Aave and Compound. Traded on Uniswap. Earns yield in various liquidity pools.

Actual BTC held by BitGo as custodian. Every WBTC backed 1:1 by real Bitcoin in BitGo's custody.

2024 brought controversy. BitGo announced plans to transfer WBTC custody to a joint venture involving Justin Sun's company. DeFi community reacted badly. MakerDAO and other protocols started offboarding WBTC as accepted collateral. Concern: if the custodian changes hands to someone with a complicated reputation, the trust backing the peg changes too.

Shows how custodian identity matters. WBTC's value isn't just in the code. It's in who holds the underlying Bitcoin. Change that, change the risk profile entirely.

WETH: Why Wrapped ETH Exists

Slightly confusing one. ETH is on Ethereum. Why does it need wrapping.

ETH predates the ERC-20 token standard. It's the native gas token. Not technically ERC-20 compatible. Most DeFi smart contracts require ERC-20 tokens to interact with them.

WETH is simply ETH wrapped into ERC-20 format. Deposit ETH, receive WETH. 1:1 forever. Burn WETH, get ETH back.

Most users never think about this. Swap ETH on Uniswap, the interface automatically wraps it in the same transaction. Invisible. But every ETH that enters a Uniswap liquidity pool is technically WETH not ETH under the hood.

The Risk Nobody Thinks About Until It Happens

Peg only holds if the underlying asset stays locked.

Bridge or custodian gets exploited. Wrapped tokens outstanding but nothing backing them. Peg collapses.

Wormhole bridge hack February 2022. Attacker exploited a smart contract vulnerability. Minted 120,000 wETH on Solana without depositing real ETH. $320 million in wrapped tokens created from nothing. Peg broke.

Ronin bridge hack March 2022. $625 million drained from the bridge backing Axie Infinity's ecosystem. Wrapped tokens on the game chain suddenly undercollateralized.

Wrapped tokens are only as safe as the mechanism holding the underlying. Smart contract bugs, custodian insolvency, validator key compromises. All have happened. All will happen again somewhere.