Ex-Apple Engineer Launches Crypto Visa Card with Private Blockchain and Zero-Knowledge Proofs

A former Apple iOS engineer has launched a crypto-linked Visa card designed to shield transaction details from public blockchains. The Payy card, developed over three years, employs cryptographic techniques like zero-knowledge proofs (ZKPs) and a custom-built blockchain to ensure that stablecoin transaction amounts remain private and do not appear on-chain [1]. This addresses a growing concern around the transparency of blockchain data, which can expose users’ financial activity to tracking and profiling [2].

Sid Gandhi, CEO of Polybase Labs and co-founder of Payy, argues that offering financial services on public blockchains—where every transaction is permanently visible—may be ethically and legally questionable under frameworks like the General Data Protection Regulation (GDPR). “You just can't build a financial system without the core pillar of confidentiality,” he stated, emphasizing the need for privacy in digital finance [2]. Unlike existing privacy-focused blockchains like Zcash or Monero, Payy is built with compliance in mind, ensuring that anti-money laundering (AML) standards are maintained without compromising user privacy [2].

The card works by leveraging ZKPs to authorize payments when the card is tapped, followed by a near-instant blockchain transaction that settles with Visa. This allows for seamless, private payments without exposing the transaction amounts or the user’s financial activity on public ledgers. According to the company, the Payy card offers one of the simplest onboarding experiences in the crypto and digital finance space [2].

Gandhi also highlighted the broader implications of blockchain transparency, warning of a future where on-chain activity could be linked to personal identities through IP addresses or social media profiles. This could open the door to more intrusive forms of financial surveillance [2]. Payy’s approach aims to mitigate these risks by design, embedding privacy and compliance into its foundational architecture [1].

The Payy Visa card represents a step toward reconciling the privacy expectations of users with the compliance requirements of financial institutions. By building a custom blockchain that supports private, stablecoin-based transactions, the team behind Payy is attempting to create a more secure and user-friendly alternative to traditional crypto wallets and payment methods [1]. The product is positioned as a bridge between the growing crypto ecosystem and the need for financial confidentiality in a world where digital footprints are increasingly scrutinized.

Source: [1] Ex-Apple Engineer Unveils Privacy-Focused Crypto Visa Card (https://www.coindesk.com/business/2025/08/06/ex-apple-engineer-unveils-privacy-focused-crypto-visa-card)

[2] Ex-Apple Engineer Unveils Privacy-Focused Crypto Visa Card (https://finance.yahoo.com/news/ex-apple-engineer-unveils-privacy-140000717.html)