Ex-Apple Engineer Unveils Privacy-Focused Crypto Visa Card

Three years in the making, the Payy Visa card hides stablecoin transactions using clever cryptographic proofs and a custom-built ledger, avoiding the situation where non-custodial card spending can be looked up and traced on public blockchains.

Former Apple iOS engineer Sid Gandhi, co-founder of the team that built the Payy card, thinks it’s irresponsible, unethical, even borderline illegal – taking General Data Protection Regulation (GDPR) into consideration – to offer users on-chain financial services where every single transaction and balance is publicly visible on the blockchain forever.

“Either I'm crazy or everyone else is crazy, because you just can't build a financial system without the core pillar of confidentiality,” Polybase Labs CEO Gandhi said in an interview.

“We spent two years building a layer two payments network from scratch. We didn't use EVM [Ethereum Virtual Machine-compatible blockchain] or anything like that, because they're not usable for private payments,” he added.

In the same way that people’s online activity is tracked and exploited, a “scary future” lies ahead where it’s possible to start relating IP addresses to blockchain wallets, meaning on-chain activity can be matched to emails, Instagram or Facebook profiles, according to Gandhi.

Under the hood, Payy uses zero-knowledge proofs (ZKPs) to allow an authorization when tapping the card; a Payy Network blockchain transaction then debits the amount from the user’s wallet to quickly settle with Visa.

The Payy team took inspiration from privacy networks like Zcash, Monero and Aztec, Gandhi said. But unlike these earlier privacy blockchains, Payy was focused from the beginning doing private stablecoin transactions in a regulatory compliant manner, avoiding obstacles that would hamper acceptance and user uptake.

“All the other existing privacy technologies don't have this idea of compliance baked in," Gandhi said. "We've been thinking about compliance and privacy for a very long time, and realized that you have to continue doing the existing AML [anti-money laundering] and compliance operations, even if you have a privacy network.”

As well as solving for privacy, Gandhi claims his card has the easiest onboarding and user experience of any wallet and crypto payment offering on the market.

“I have tried everything. Even my sophisticated non-crypto friends will never be able to use any of these solutions. I can say that confidently. Our philosophy is that the product should be usable by anyone and everyone. Every single iteration of an on-chain bank for the last 10 years that we have seen is not usable." he said.

To date, Payy builder Polybase Labs has raised funds from Robot Ventures, DBA Crypto, 6th Man Ventures, Orange DAO, Protocol Labs and others.

“Payy finally built a real alternative to consumer banking,” said Robot Ventures partner Robert Leshner, in a statement. “You can now save and spend self-custodied stablecoins privately without ever knowing they’re on a blockchain. And it just works.”