Privacy products fail when the wallet is an afterthought

I worked as a Senior Product Owner at Input Output · IOHK from January 2022 to August 2023. My scope covered four product areas for Midnight, Cardano’s data-protection sidechain: the Midnight Wallet, Midnight DAO, Pub-Sub Indexer, and Midnight blockchain stack.

The product question was practical: how do you help people and organizations share mission-critical information in a connected world while protecting sensitive data? Midnight’s goal, as I understood it, was to make data-protection blockchain technology accessible. That meant supporting transactions, participation in governance, and sharing sensitive information with greater control over what people disclose.

If you want the broader career context first, start with Who is Sunil Vallath? This essay focuses on one product chapter and the connection between its user-facing and infrastructure work.

Privacy has to appear in the user’s work

A privacy product is not finished when the cryptography is impressive. It is useful when the person using it can understand what is protected, what they are doing, and what they are choosing to disclose.

That is why the wallet matters. The Midnight Wallet was a private wallet designed to help users protect sensitive information during cryptocurrency transactions. Its approach centered on zero-knowledge proofs (ZKPs), making privacy part of the transaction experience.

This is a product distinction, not a research footnote. If privacy only exists below the interface, users still have to make decisions without a clear connection between the technology and the action in front of them. The wallet is where the abstract promise meets a transaction.

Governance is another privacy surface

The same problem appears when the action is not a payment. I owned development of the Midnight DAO, a private DAO covering transactions and organizational decision-making.

The product applied zero-knowledge proofs to help protect participants’ identities and personal information as they took part in governance. That makes privacy part of participation itself. People are not only sending value; they are taking part in decisions, and the product has to account for the information attached to that participation.

A private governance product therefore has two jobs: support the decision-making process and give participants greater control over their personal information. The second job is not decoration around the first. It is part of whether participation feels safe enough to use.

Infrastructure still shapes the experience

The visible wallet and DAO depend on the systems beneath them. My scope also included the Pub-Sub Indexer and the Midnight blockchain stack.

The Pub-Sub Indexer was a publish-subscribe product tailored to blockchain transactions and events related to zero-knowledge proofs. Its purpose was to index and process that activity so it could be retrieved efficiently.

I was also responsible for development of a comprehensive blockchain stack as Product Owner for the Midnight blockchain. That extended the work to the underlying platform supporting Midnight’s data-protection products.

This is the part of privacy product work that is easy to miss. A user may experience a wallet or a governance flow, but the product depends on indexing, processing, and platform support underneath. A privacy promise has to travel across that whole path.

The product lesson

My work across these four areas shaped a simple view of privacy product development:

1. Start with the action. The wallet connected zero-knowledge proofs to cryptocurrency transactions.
2. Treat participation as a product flow. The private DAO applied ZKPs to governance and the protection of participants’ identities and personal information.
3. Give infrastructure a user-facing purpose. The Pub-Sub Indexer processed and indexed relevant transactions and events so the activity could be retrieved efficiently.
4. Connect the layers. The wallet and private DAO experiences depended on the indexing infrastructure and blockchain stack beneath them.

The point is not to make every user learn the stack. The point is to make data-protection technology accessible while giving people greater control over what they disclose.

Privacy products fail when the wallet is an afterthought because the wallet is where the user meets the promise. But the wallet cannot carry that promise alone. Governance, indexing, and the blockchain stack have to support the same product intent: transact, participate, and share sensitive information with more deliberate control over disclosure.

FAQ

What is a privacy wallet product? A product where privacy is part of the transaction experience itself. For Midnight, a private wallet used zero-knowledge proofs so users could protect sensitive information during cryptocurrency transactions, not only rely on cryptography below the interface.

How do ZKPs change the UX job? They move the product job from explaining cryptography to making disclosure choices understandable in the action: what is protected, what the user is doing, and what they are choosing to share, in the wallet and in private governance.

What did Midnight wallet vs DAO ownership cover? Wallet ownership centered ZKPs in private cryptocurrency transactions. DAO ownership applied ZKPs to a private DAO covering transactions and organizational decision-making, protecting participants’ identities and personal information during governance. Scope also included Pub-Sub Indexer and blockchain stack underneath.

Related reading: shipping when regulation closes the chapter, building products people actually use, and who is Sunil Vallath?. For more on the work described here, see Input Output and Midnight Network.