Harpocrates

Harpocrates is a Stellar Testnet evidence protocol for sensitive video. It registers video integrity, portable proof metadata, and one of three identity tiers:

• Silent Witness: anonymous credential proof with nullifier replay protection.
• Consistent Source: pseudonymous Stellar wallet source.
• Public Seal: verified institutional issuer.

Workspace

frontend/   React app for Evidence Studio and Verification Portal
backend/    Flask video metadata service
contracts/  Soroban contract workspace
project.md  Product and architecture spec
DESIGN.md   Visual design source

Quick Start

1. Backend

cd backend
python -m venv .venv
.\\.venv\\Scripts\\Activate.ps1
pip install -r requirements.txt
python app.py

Backend runs at http://127.0.0.1:5050.

2. Frontend

cd frontend
npm install
npm run dev

Frontend runs at http://localhost:5173.

3. Contracts

cd contracts
cargo test
stellar contract build

Stellar Testnet Deployment

Create or select a Stellar identity:

stellar keys generate harpocrates-admin --network testnet --fund

Build and deploy:

cd contracts
stellar contract build
stellar contract deploy `
  --wasm target\\wasm32-unknown-unknown\\release\\harpocrates_registry.wasm `
  --source harpocrates-admin `
  --network testnet

After deployment, put the contract ID in frontend/.env.local:

VITE_HARPOCRATES_REGISTRY_ID=YOUR_CONTRACT_ID
VITE_API_BASE=http://127.0.0.1:5050
VITE_STELLAR_RPC_URL=https://soroban-testnet.stellar.org
VITE_STELLAR_READONLY_SOURCE=YOUR_FUNDED_TESTNET_ACCOUNT

Current Testnet deployment:

HarpocratesRegistry=CCKTQNMBLXZXMWVR2WG4HDDUI3QGJU5LV5NTLFPCB72UITWE5TEDK7BT
SilentWitnessUltraHonkVerifier=CCP2EQPKT5XAYTOARX3LGHNMJ37A6W2WY3H54MRIHEZVTVAZZPUSGZQJ
Admin=GDVRSXIO4SK2KSMUKJTQHMDDHBBFC7NGZZ6WLVOPKAG47GYPYAZCZR7G
Issuer=GAJ3GSKWOCTI2B3ZQRTB7TWYYIX734VJLNGOMSIQSAGRMIGX6SSVMIB4
RegistryWasmHash=a0e9bd49967bae7cb3608166b323514c8ef46832905f56b3c4a5aff41e105e68

Live check:

register_anonymous_verified with active credential root succeeded on Testnet.
Last E2E tx=c2d02db6cb2453650987cfb475b21184c558c5437cdef2bd02969f39db021616

Current Implementation Status

Done:

• React Evidence Studio and Verification Portal shell.
• Local SHA-256 video hashing.
• Three identity tier UI.
• Flask video steganography service with border encoding and LSB fallback.
• NeonDB proof event storage.
• Registration event persistence after Stellar submission.
• Verification portal lookup across embedded metadata, NeonDB, and Soroban get_by_video.
• Real Noir Silent Witness circuit with UltraHonk proof generation and local verification.
• Browser-side Noir JS and bb.js prover for user-seeded, video-specific Silent Witness proofs.
• Soroban registry with all three identity paths.
• Soroban registry hook for a dedicated Noir UltraHonk verifier contract.
• Credential-root allowlist/revocation, issuer registry, and nullifier protection.
• Contract tests for all tiers.
• One-command E2E smoke test for steganography, browser-compatible Noir proving, NeonDB, and optional Stellar Testnet registration.
• Typed frontend registry client and manual production chunking for Stellar, Noir, React, and proof runtime bundles.
• Backend production hardening: security headers, readiness checks, stricter upload/metadata validation, safer CORS config, and production-gated local Noir worker.
• Typed Soroban contract events with #[contractevent] for proof, issuer, verifier, and credential-root lifecycle events.

Next:

• Hosted deployment packaging for frontend/backend environments.

E2E Smoke Test

Run the local E2E path:

.\scripts\e2e-harpocrates.ps1

This creates a synthetic video, embeds Harpocrates metadata, extracts it back, generates a browser-compatible Noir UltraHonk proof, writes a NeonDB registration event, and checks lookup by the embedded video hash.

Submit the same flow to Stellar Testnet:

.\scripts\e2e-harpocrates.ps1 -RegisterOnChain

The on-chain mode calls register_anonymous_verified, verifies the returned contract record matches the embedded video hash, then stores the transaction result in NeonDB.

For a fresh registry that enforces active Silent Witness credentials, use:

.\scripts\e2e-harpocrates.ps1 -RegisterOnChain -EnsureCredentialRoot

Deploy a fresh Testnet registry and run E2E:

.\scripts\deploy-testnet.ps1

Noir Proofs

Tier 1 now has a real Noir circuit in zk/noir/silent_witness.

Run from PowerShell:

.\zk\noir\scripts\build-silent-witness-wsl.ps1

Current verified local toolchain:

nargo 1.0.0-beta.9
bb 0.87.0
UltraHonk proof verified successfully

Export proof artifacts as hex:

.\zk\noir\scripts\export-silent-witness-artifacts.ps1

Generate a video-specific proof with caller-provided field secrets:

.\zk\noir\scripts\generate-silent-witness-wsl.ps1 `
  -VideoHash YOUR_32_BYTE_HEX `
  -CredentialSecret YOUR_FIELD_DECIMAL `
  -NullifierSecret YOUR_FIELD_DECIMAL

The registry now exposes register_anonymous_verified and can call a separate verify_proof(public_inputs, proof) contract. It also requires the public credential_root from the Noir proof to be active in the registry.

The frontend uses the same Noir artifacts from frontend/public/noir to produce Silent Witness proofs in the browser. To smoke-test that path in Node:

cd frontend
node scripts/test-noir-client-prover.mjs

Backend API

GET  /health
POST /api/stego/embed
POST /api/stego/extract
POST /api/noir/silent-witness
GET  /api/proofs?limit=25
GET  /api/proofs/by-video/:video_hash
POST /api/proofs/register

/api/stego/embed returns an embedded video/mp4 artifact. The response headers include:

X-Harpocrates-Source-Hash
X-Harpocrates-Embedded-Hash
X-Harpocrates-Metadata-Hash

The frontend registers X-Harpocrates-Embedded-Hash on Stellar, so verifiers hash the received embedded video and look that hash up on-chain.

/api/noir/silent-witness remains available as a local developer prover for a specific videoHash. The product flow uses browser-side Noir JS and bb.js instead, so user private seeds are not sent to the Flask service.

/api/proofs/register stores the Stellar transaction result in NeonDB:

{
  "fileName": "evidence.mp4",
  "videoHash": "32-byte hex",
  "metadataHash": "32-byte hex",
  "proofId": "32-byte hex",
  "tier": "source",
  "txHash": "stellar transaction hash",
  "txStatus": "PENDING",
  "sourceAddress": "G...",
  "contractId": "C..."
}

Contract Scripts

PowerShell helpers live in contracts/scripts.

.\contracts\scripts\add-issuer.ps1 `
  -ContractId CC2RBQ4GRGWNXMIW5OUL3HGQ5LCNUK7DCMZ76EEFZCPCXMTAGQ33Y5MY `
  -Admin harpocrates-admin `
  -Issuer harpocrates-issuer `
  -MetadataHash YOUR_32_BYTE_HEX

.\contracts\scripts\register-seal.ps1 `
  -ContractId CC2RBQ4GRGWNXMIW5OUL3HGQ5LCNUK7DCMZ76EEFZCPCXMTAGQ33Y5MY `
  -Issuer harpocrates-issuer `
  -VideoHash YOUR_32_BYTE_HEX `
  -MetadataHash YOUR_32_BYTE_HEX `
  -ProofId YOUR_32_BYTE_HEX

.\contracts\scripts\set-verifier.ps1 `
  -ContractId YOUR_REGISTRY_CONTRACT_ID `
  -Admin harpocrates-admin `
  -Verifier YOUR_VERIFIER_CONTRACT_ID

.\contracts\scripts\add-credential-root.ps1 `
  -ContractId YOUR_REGISTRY_CONTRACT_ID `
  -Admin harpocrates-admin `
  -CredentialRoot YOUR_32_BYTE_HEX `
  -MetadataHash YOUR_32_BYTE_HEX

.\contracts\scripts\revoke-credential-root.ps1 `
  -ContractId YOUR_REGISTRY_CONTRACT_ID `
  -Admin harpocrates-admin `
  -CredentialRoot YOUR_32_BYTE_HEX