ZKAgeWallet: Private Age Verification Wallet

💡 Inspiration

In the digital age, proving a simple fact—like being over 18 years old—forces users to compromise their entire identity. Whether online or in person, verifying eligibility requires revealing a national ID, exposing sensitive data such as full names, exact birthdates, and residential addresses. This creates a massive attack surface for identity theft and data leaks.

We were inspired to build ZKAgeWallet to decouple identity from eligibility. We wanted to answer a fundamental Web3 question: How can a user prove they meet a criteria without revealing who they are?

⚙️ How We Built It

Since this project was designed as a rapid proof of concept (PoC) for the Midnight Hackathon, we focused heavily on user experience, business logic, and architectural design:

• UI/UX Ideation: We mapped out a frictionless mobile wallet experience where cryptographic complexity is completely hidden behind a clean user interface.
• Cryptographic Architecture: We designed the theoretical framework for how a Zero-Knowledge Proof (ZKP) system would interact with a trusted identity issuer and a third-party verifier.
• AI Collaboration: We utilized advanced LLMs to brainstorm the tech stack integration, refine the business logic, and draft the cryptographic verification flow.

The Underlying Math (ZKP Logic)

To demonstrate compliance with the Midnight Network's privacy standards, the system relies on a non-interactive zero-knowledge argument. Let $x$ be the user's secret birthdate, and $f(x)$ be the public validation function defined as:

$$f(x) = \begin{cases} 1 & \text{if } \text{CurrentYear} - x \ge 18 \ 0 & \text{otherwise} \end{cases}$$

Instead of sending $x$ to the merchant, the wallet generates a proof $\pi$ such that:

$$\text{Verify}(\text{Public Inputs}, \pi) = \text{True}$$

The merchant only receives the cryptographic confirmation ($\text{True}$), meaning the user's raw identity variables remain entirely local and encrypted on their device.

🚧 Challenges We Faced

As a beginner-friendly project built within a strict 48-hour window, our biggest challenges were:

1. Navigating Privacy Frameworks: Understanding how to translate dense cryptographic concepts (like Zero-Knowledge Proofs) into an intuitive visual application flow.
2. Time Constraints: Balancing the technical design of a Web3 infrastructure while ensuring a polished presentation under a tight deadline.
3. Solitary Development: Managing the entire pipeline from conceptualization to the final pitch as an individual participant required strict scope management.

🧠 What We Learned

This hackathon was an incredible learning accelerator. Through this process, we:

• Mastered the core philosophy of Self-Sovereign Identity (SSI) and how privacy-centric blockchains like Midnight change data ownership.
• Learned how to effectively pitch a complex technical product by focusing on user benefits rather than just backend jargon.
• Discovered how to leverage AI tools as interactive technical co-pilots to accelerate research and development under pressure.

Built With

• backend
• cryptography
• data
• figma
• markdown
• python
• zero-knowledge-proofs