BLK whale is a Defi protocol for creating encrypted ETF derivatives. In Defi, various ETF derivatives that cannot be completed in Cefi are realized. Users can mint ETF tokens designed to track indices of various valuable tokens from multiple exchanges around the world in real time. BLK Whale manages ETF tokens together with USDB tokens, ensuring that there is always enough collateral in the agreement to cover ETF tokens. The minting of ETF tokens is decentralized, allowing users to open positions and deposit collateral. In addition, ETF tokens disclose the real assets of the tokens to support traders to trade these assets with more confidence.