Wrapped tokens and bridges: moving assets between blockchains
How a coin from one network appears on another, what backs a wrapped token, and why bridges are a common target for attacks.
Blockchains do not talk to each other natively. Bitcoin cannot be used directly in Ethereum applications. Wrapped tokens and bridges fill this gap.
What a wrapped token is
A wrapped token represents an asset from another chain. WBTC, for example, is an ERC-20 token on Ethereum that is meant to be backed one-to-one by bitcoin held by a custodian. Holding WBTC gives exposure to bitcoin's price inside Ethereum applications. The coin page for WBTC on XFasil shows its market against USDT.
Lock and mint
Most bridges follow the same idea:
- You send the original asset to the bridge, which locks it.
- The bridge mints the same amount of a wrapped token on the other chain.
- To go back, you burn the wrapped token, and the bridge releases the original.
Who controls the locked assets and who decides when to mint are the key security questions.
Types of bridges
- Custodial: a company or group of signers holds the original assets.
- Smart-contract based: contracts and a set of validators verify events on both chains.
- Native and rollup bridges: layer 2 networks have bridges secured by the main chain, often with withdrawal delays.
Risks
Bridges hold large pools of locked assets, which makes them attractive targets. Bugs, stolen signer keys or faulty verification have led to some of the largest losses in crypto history. A wrapped token is only as safe as the bridge or custodian behind it.
Practical rules
- Use bridges and wrapped tokens only from official sources.
- Check the exact token contract — many fake "wrapped" tokens exist.
- Expect waiting times and fees on both chains.
On XFasil, deposits and withdrawals use only USDT on the TRON (TRC-20) network. No bridging is involved.
Blog posts are for education and information only and are not investment, legal or tax advice.