Bridging across chains
Blockchains are islands. A bridge moves value between them — and it's one of the most dangerous corners of the ecosystem.
Blockchains are islands: an asset on Ethereum and one on another chain live on separate ledgers with no native way to see each other. A bridge moves value between them, and it's one of the most dangerous corners of the ecosystem.
How a bridge actually works
You can't literally "send" an ETH to another network, because that network's ledger doesn't recognize Ethereum's. So bridges use workarounds — most commonly lock-and-mint:
- You deposit the real asset into the bridge's contract on the source chain, where it's locked.
- The bridge mints an equivalent wrapped token on the destination chain, backed (in theory) by the locked original.
- To go back, you burn the wrapped token and the bridge releases the original.
The wrapped token is an IOU — only worth something as long as the locked collateral is actually there and redeemable.
That's exactly the vulnerability
Bridges concentrate enormous value in a single set of contracts holding everyone's collateral, making them the richest targets in crypto.
- The Ronin Bridge lost roughly $625M in March 2022 when attackers compromised five of its nine validator keys (attributed to North Korea's Lazarus Group).
- Wormhole lost about $320M in February 2022 through a signature-verification bug that let an attacker mint 120,000 wrapped ETH from nothing.
- Cumulatively, bridge exploits have caused well over $2.5B in losses.
When a bridge is drained, the locked collateral vanishes and the wrapped tokens become worthless instantly. The risk sits in three places: the bridge's contracts, the honesty of whoever validates cross-chain messages, and the integrity of the wrapped asset.
Practical discipline
- Prefer official or canonical bridges over obscure third-party ones.
- Don't bridge more than you need, and don't leave large balances in wrapped assets longer than necessary.
- Double-check the destination network and address — cross-chain mistakes are often unrecoverable.
- Treat every bridge crossing as a risk event, not a routine transfer.
Why it matters. Bridges expose a deep truth: this isn't one unified system but an archipelago of sovereign networks that don't naturally trust each other. The dream is seamless interoperability; the reality is that every connection between trustless systems reintroduces exactly the trusted middleman crypto set out to eliminate — and that middleman becomes a single point of failure holding everyone's money.