zkFair is a framework for generating and verifying zero-knowledge proofs of ML model fairness. Providers register models, commit query batches, and respond to fairness audits — all using ZK proofs on-chain. Users get cryptographic guarantees that deployed models satisfy demographic parity, without the provider ever revealing model weights or training data.
Two Noir ZK circuits enable privacy-preserving fairness verification:
- Training Certification — proves a model satisfies demographic parity on its training dataset, without revealing weights or data
- Batch Auditing — proves ongoing fairness on random samples from deployed inference batches, enabling continuous runtime monitoring
A Solidity smart contract enforces honest participation through staking and slashing:
- Providers stake ETH to register models; dishonest behavior (missed audits, invalid proofs) results in stake forfeiture
- Auditors stake to challenge batches; valid challenges are rewarded from the provider's stake
- 24-hour response deadlines with automatic slashing for non-compliance
Users receive signed receipts for every inference query. The Sentinel system detects two classes of provider fraud:
- Non-inclusion — a query was made but never appeared in any committed batch
- Fraudulent inclusion — a query was batched with tampered data (different features or prediction)
Both dispute types are provable on-chain using the signed receipt as evidence.
A production-ready TypeScript SDK and toolchain:
- SDK (
@zkfair/sdk) — core library with contract interaction, proof generation, Poseidon hashing, Merkle trees, and provider/client utilities - ZK Circuits (
@zkfair/zk-circuits) — Noir circuits compiled to UltraHonk via@aztec/bb.js - Smart Contract (
@zkfair/contracts) — Solidity contract with model registry, batch commitments, audit lifecycle, and dispute resolution - Apps — CLI for providers, React dashboard, inference server, and off-chain attestation service
apps/
cli/ Command-line interface for providers
web/ React dashboard (model registry, audit tracking)
server/ Hono inference server (ONNX model, query logging, auto-batching)
attestation/ Off-chain proof verification + signed attestations
www/ Landing page + documentation site
packages/
sdk/ TypeScript SDK shared across all apps
contracts/ Solidity smart contract (Foundry)
zk-circuits/ Noir ZK circuits (training + fairness audit)
# Install dependencies
bun install
# Run all apps in dev (starts local anvil chain + all services)
bun run dev
# Run a single app
turbo run dev --filter=web
turbo run dev --filter=server
# Build everything
turbo run build
# Run contract testscd packages/contracts && bun run test# Run SDK testscd packages/sdk && bun test# Compile ZK circuitscd packages/zk-circuits && bun run compile