Chain-key WBTC (ckWBTC), a multi-chain WBTC twin on the Internet Computer, is an ICRC-1-compliant token that is backed 1:1 by WBTC such that 1 ckWBTC can always be redeemed for 1 WBTC and vice versa. The ckETH minter canister is responsible for both minting ckWBTC tokens when users transfer WBTC to its control and burning ckWBTC when handling WBTC retrieval requests. ckWBTC transactions are facilitated through a ledger canister, which in conjunction with archive canisters, tracks ckWBTC account balances and transaction history between accounts. An index canister provides access to ckWBTC transactions associated with individual accounts.