Protecting On-Chain Privacy When Using Cash DeFi Card The new generation of decentralized finance (DeFi) credit cards represents a major leap in how users can access and use their digital assets. Cash allows users to spend stablecoins while generating 5.6% APY or borrow against yield-bearing assets, enabling real-world spending without selling their underlying crypto holdings. However, while this innovation brings crypto utility closer to everyday life, it also highlights a general limitation of public blockchains — asset and transactional transparency. When users fund any on-chain card account from a personal wallet, that transaction, like all blockchain transfers, is publicly visible. This means the movement of assets between a user’s primary wallet and their new card account can, in principle, be analyzed on-chain. Over time, such transparency can make it easier to associate spending wallets with broader portfolio activity. This is not unique to any single product; it’s a structural characteristic of transparent blockchain systems. As DeFi expands into real-world payments through innovations like Cash, maintaining privacy between investment and spending activity becomes an important consideration for users who value financial confidentiality. Introducing a Privacy-Preserving Solution: Hinkal Wallet Hinkal is a self-custodial, private smart contract wallet that enables users to interact with DeFi applications without revealing their financial data. By funding Cash through Hinkal, users can effectively break the on-chain link between their primary wallets and their DeFi cards, preserving privacy without compromising functionality. This approach ensures that spending activities remain independent from users’ broader investment and savings portfolios. How It Works: Deposit into Hinkal Private The user deposits the amount they intend to use for Cash into their private Hinkal Wallet. This deposit is visible on-chain, but the trail ends at the Hinkal shielded pool. Unshield to Hinkal Public Unshield the amount you’d like to send to your Cash vault. Transfer from Hinkal The trace ends with Hinkal shielded pool, enabling the right hygiene of your spending account without revealing the source wallet. Through this method, users can fund and use their @ether_fi .fi Cash card without exposing their financial graph - achieving on-chain privacy with full DeFi compatibility. A Step Toward Safer On-Chain Finance As DeFi integrates deeper into real-world financial systems, privacy must evolve alongside accessibility. The use of Hinkal with Cash highlights a new standard for on-chain usability — where users can transact, borrow, and spend confidently, knowing their financial data remains private and secure.