A new suite of modern payments solutions has rolled out over the past decade during fintech’s boom. These products have helped make moving money more seamless and social—but they have also raised questions about how user data is collected, stored, and shared.

The following are three categories of payments products that have elicited market and regulatory concern over their potential to compromise privacy.

Biometrics

Payments solutions using users’ biometric data have proliferated in the past five years. From Amazon’s “Just Walk Out” technology to Worldcoin’s fledgling infrastructure, consumers have encountered a growing ecosystem of products that leverage users’ nonfungible biological information to carry out transactions.

But privacy experts warn that these technologies have serious privacy implications. According to Hafiz Malik, an electrical- and computer-engineering professor at the University of Michigan, new developments in AI could spoof users’ identifiers to carry out fraudulent transactions. What’s more, having a user’s palm print or eye scan hacked can have a far greater impact on a user’s financial security over the long run as compared to having one’s credit card number stolen.

“It’s something everyone should care about protecting, even in this age where many people feel like they’ve given up on protecting their privacy or feel like it’s futile,” said Evan Greer, a digital rights advocate, in an interview with CNBC.

The blockchain

Blockchain-based products do contain some intrinsic safeguards that make their operation more resilient than centralized counterparts. Through distributed-ledger technology, blockchain-based payments solutions offer immutability, making it virtually impossible to spoof transaction history for nefarious purposes.

However, the blockchain’s openness makes it difficult to hide transaction flows and keep payments private. Even with layer 2 solutions conferring some degree of anonymity, the blockchain’s relative transparency and accessibility may turn enterprise clients away.

Social payments feeds

In an effort to grow, peer-to-peer payments platforms like Venmo have leveraged social media methodologies to turn payments into an interpersonal and entertaining product. Through their social feeds, these platforms can let users track, like, and comment on their friends’ transactions.

While this has successfully merged social media with payments for many consumers, these platforms should do more to effectively communicate their default privacy settings and the discoverability of potentially sensitive transactions.