---
title: ZK Credentials
titleTemplate: Guides
description: Public guide to zero-knowledge credential presentations in KryptoOS.
---
ZK credentials let a user prove a fact without revealing the underlying private data.

## Public Examples

| Proof | Reveals | Does Not Reveal |
|-------|---------|-----------------|
| Age over 18 | `ageOver18: true` | birth date, document number |
| KYC approved | approval status | name, address, document scan |
| Sufficient balance | threshold satisfied | exact balance |

## Developer Flow

1. The issuer creates a credential for the holder.
2. The holder generates a selective proof or ZK presentation.
3. The verifier checks proof validity, expiry and revocation status.
4. If an on-chain check is required, the app submits only the proof commitment and public inputs needed for verification.
5. Public activity can be linked to EmpooScan when indexed.

## Privacy Rule

Do not place raw identity documents, full names, addresses, birth dates, raw balances, device IDs or private proofs in public logs or transaction metadata.

## Status

The website documents the public integration model. Exact circuits, proving keys and internal verifier configuration are published only when they are release-ready and safe for public distribution.