This project allows you to deposit and withdraw Bitcoin on the Oasis Sapphire confidential blockchain. Deposits of specific sizes (powers of 2) can be converted into LiquidBTC, an ERC-20 compatible token, which can in return be exchanged for real BTC.
It uses an on-chain Bitcoin SPV light-client to verify deposits have been made to addresses generated by the BTCDeposit contract. To redeem the underlying BTC a deposit can be 'burned' which reveals the secret key and address to the holder, meaning 'un-burned' BTC deposits can be freely traded or converted to & from LiquidBTC tokens because the secret key can't leak without it being evident.