ckBTC

ckBTC is a chain-key token that represents Bitcoin on the Internet Computer. Every ckBTC token is backed 1:1 by real BTC on the Bitcoin blockchain, with minting and burning handled by the ckBTC minter canister on the IC.

Key concepts

Native Bitcoin integration

ckBTC is not a wrapped asset bridged through an external custodian. Instead, the Internet Computer integrates directly with the Bitcoin network, enabling canisters (smart contracts) to hold, send, and receive BTC securely.

Chain-key cryptography

Chain-key cryptography allows the IC to sign Bitcoin transactions as a single logical entity. This ensures ckBTC always maps directly to BTC without relying on trusted intermediaries.

ICRC token standards

The ckBTC ledger implements ICRC-1 (fungible tokens) and ICRC-2 (approvals and delegated transfers) token standards. Developers interact with the ledger through these standard endpoints for transfers, balance queries, and approvals.

Learn more about ckBTC.

How it differs from Lightning

The Lightning Network is the most well-known Layer-2 for Bitcoin. Like ckBTC, it enables fast and inexpensive transfers of BTC value off the Bitcoin blockchain.

There are, however, key differences:

No payment channels required

Lightning depends on establishing and funding peer-to-peer payment channels. ckBTC does not. A ckBTC balance is always liquid and transferable without channel liquidity constraints.

Smart contract compatibility

ckBTC can be held and transferred directly by canister smart contracts. This makes it possible to build fully on-chain Layer-2 applications for Bitcoin — something not possible with Lightning.

Fixed fees

ckBTC transaction fees are predictable and independent of transfer amount. Lightning fees can vary depending on routing, forwarding, or the need to fund additional channels.

Why ckBTC unlocks DeFi for Bitcoin

Lightning makes peer-to-peer Bitcoin payments faster and cheaper, but it is not designed for onchain programmability. ckBTC extends Bitcoin into the Internet Computer ecosystem, where smart contracts can hold and transfer BTC directly.

This unlocks new DeFi use cases, such as:

• lending and borrowing markets secured by Bitcoin,
• decentralized exchanges and trading pairs with ckBTC,
• automated payments and DAO treasuries backed by BTC.

Because ckBTC transactions are fast, low-cost, and free of liquidity constraints, they provide the foundation for scalable and fully onchain Bitcoin DeFi.

Example applications

• ic-pos: an experimental app to demonstrate a real-world use case for ckBTC on the Internet Computer. It is a simple Point of Sale app that allows users to accept ckBTC payments.

Learn more about how to use ckBTC in your dapp.

References

• Bitcoin on the ICP Dashboard: provides an overview of all ckBTC-related information, including total supply, tracked UTXOs, synced Bitcoin block height, ckBTC canisters, and recent transactions.
  • The same overview exists for testnet4 Bitcoin
• ckBTC deep dive: a Wiki article providing an in-depth explanation of how ckBTC works.