🦰What is ID-Mask?
App Overview
This app empowers users to create zero-knowledge proofs (ZKPs) about themselves—secure, privacy-preserving attestations that reveal nothing beyond the fact being proven.
Built with a strong focus on client-side operations, the app fetches personal data using Smart-ID directly in the browser. This data is then passed into predefined zero-knowledge circuits to generate cryptographic proofs entirely on the user's device.
Users can store these proofs in their Google Wallet, Apple Wallet, or publish them on the Mina Protocol L1 blockchain.
When needed, users present their proof via a QR code. The proof verifier sees only the specific fact (e.g., "I am over 18")—no additional personal data is exposed.
This app brings real-world utility to privacy-first identity verification.
Preventing Proof Sharing
A key challenge with zero-knowledge proofs is preventing them from being shared and reused by others. For example, someone could attempt to use their older sibling’s proof of age to falsely claim they are over 21.
To solve this, we use active auth. The app embeds a passkey pair into each proof at creation time. These passkeys are cryptographic credentials unique to the user and device.
Inside the zero-knowledge circuit, a signature using this passkey pair is verified. As a result, the public key (or a pointer to it) becomes part of the proof's public output.
When presenting a proof, the user must sign a challenge using their passkey. The proof consumer verifies this signature against the public key embedded in the proof, ensuring that:
The presenter is the same individual who originally created the proof.
The proof has not been shared or reused by anyone else.
This mechanism ensures that proofs are bound to individuals and cannot be transferred or misused by others.
What Is a Proof?
A proof is a JSON object containing cryptographic evidence that a certain fact (e.g., being over 18) is true, without revealing any additional personal data.
Each proof includes:
publicInput: The value being proven (e.g.,"5"means "prove age ≥ 5").publicOutput: Public values that allow anyone to verify the proof.proof: The actual zero-knowledge proof string.maxProofsVerified: Currently unused (0by default).
Example Proof of age with explanation
{
"publicInput": ["5"], // Proving: age ≥ 5
"publicOutput": [
"5", // [0] Years to prove
"20250525", // [1] Proof creation date (YYYYMMDD)
"80987473785...969161318090", // [2–3] Mina wallet public key (split into two parts)
"0",
"14787152154564119254483407", // [4–6] Passkey public key (x-coordinates)
"63391986999191009329240727",
"15785887159263306888538961",
"73727926632129849938683848", // [7–9] Passkey public key (y-coordinates)
"86587147207223338757045216",
"11096342160664184776357244",
"8150879811412...8011810765", // [10] WebAuthn key ID
"1" // [11] Is personal data mocked? ("1" = yes, "0" = no)
],
"maxProofsVerified": 0,
"proof": "KChzdGF0b...nQoKyb29mX" // Zero-knowledge proof string
}Types of Proofs
👵 Proof of Age
Proves you're older than a specific number of years
Age-restricted sites, alcohol purchases, entry gates
Verifies age without revealing birthdate or identity
📜 Proof of Non-Sanctions
Proves you're not on OFAC or similar sanctions lists
Financial services, crypto exchanges, compliance
Enables checks without exposing personal identity
🧠 Proof of Unique Human
Proves you're a single, real, untrackable person
Voting, airdrops, Sybil resistance in web3
Prevents bots and duplicate users while preserving privacy
🏛️ Proof of Nationality
Proves which country issued your ID
National ID checks, citizenship programs, residency
Confirms nationality without sharing full ID details
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