Privacy-first proof-of-existence for files.
Timestamp file fingerprints on Base Sepolia without uploading a single byte.
| Create proof | Verify proof |
|---|---|
 |
 |
OpenProof creates verifiable timestamps for file hashes. No uploads. No accounts. No database. Select a file, hash it locally with SHA-256, register only the hash on Base Sepolia, and download a portable JSON receipt. Verify later by hashing the exact same file again — no original file ever leaves your device.
| Feature | Description |
|---|---|
| Local SHA-256 hashing | Files are hashed in-browser via the Web Crypto API. File bytes stay local. |
| Proof registration | Register bytes32 hashes on the Base Sepolia blockchain. |
| Proof verification | Re-hash local files and check against the onchain registry. |
| JSON receipts | Portable, versioned proof receipts downloaded locally. |
| Receipt import | Validate existing receipts and verify hashes onchain. |
| Local proof history | Recent proofs stored in browser local storage only. |
| Public proof pages | /proof/[hash] reads public registry state for sharing. |
| QR verification | QR-encode the proof page URL for quick mobile verification. |
| Bundle proofs | Deterministic combined hash for multiple local files. |
- Researchers — timestamp research data and preprints.
- Creators — prove ownership of digital works without uploading.
- Archivists — anchor file fingerprints to an immutable chain.
- Anyone — who needs to prove a file existed at a certain time.
"Proof before platform — let users verify existence without surrendering the file itself."
OpenProof is part of a broader direction: software that helps people prove things without surrendering the thing itself. Local-first by default. Privacy before convenience theatre. Permanence without exposure.
| Version | Date | Highlights |
|---|---|---|
| v0.1.0 | 2026-05-29 | MVP — local SHA-256 hashing, Base Sepolia proof registration, JSON receipts, bundle proofs, QR verification, proof explorer |
| v0.1.1 | 2026-06-22 | PWA support (manifest, service worker, app icons), cross-platform icon set, store metadata, release checklist |
| v0.1.2 | 2026-06-22 | Light/dark theme toggle, native About / Privacy / Terms pages, Block/Cash App UI revamp |
| v0.1.4 | 2026-06-23 | Trust & Transparency — About page redesign, architecture diagram, threat model, registry transparency |
| v0.2.0 | 2026-06-25 | Cryptographic Foundation — receipt schema v3, registry abstraction layer, wallet state handling |
| v0.3.0 | 2026-06-25 | Merkle tree bundle proofs, bundle explorer (/bundle/[hash]), bundle storage |
| v0.4.0 | 2026-06-25 | Professional evidence workflows — timezone support, citation formats (APA/MLA/Legal), human-readable receipt view + print/PDF, QR improvements |
| v0.5.0 | 2026-06-25 | Verification engine — full receipt validation pipeline (11+ checks), VerificationReport |
| v0.6.0 | 2026-06-25 | Long-term preservation — archive package export, hash algorithm abstraction, compatibility checks |
| v0.7.0 | 2026-06-25 | Explorer improvements — bundle awareness on proof pages, canonical URLs, chain-aware explorer |
| v0.8.0 | 2026-06-25 | Release Hardening — error boundary, offline detection, CSP security headers, store readiness |
| v0.9.0 | 2026-06-25 | Native Platform Readiness — MSIX packaging, Android (Capacitor), PWA polish, domain migration |
| v0.9.1 | 2026-07-02 | Open Product Family branding — lockup alignment, Kovina Collection footer, dual-theme icon overhaul |
| v0.9.2 | 2026-07-04 | GeneratedAssets replacement, Kovina footer, PWA icon refresh, README overhaul |
| v0.9.3 | 2026-07-04 | Installed PWA App Experience — /app workbench, splash screen, bottom nav, compact header, display-mode detection |
- Live app
- BaseScan contract
- Development setup
- Architecture
- Deployment
- Testing
- Contributing
- Receipt specification
- Threat model
- Privacy policy
- Terms of service
- Changelog
AGPL-3.0-only. See LICENSE.
Part of the Kovina Collection
OpenReader · OpenJournal · OpenLedger · OpenTone · OpenPalette · OpenConvert
OpenSnap · WorldClock Widget · OpenProof · OpenSend · OpenSprout
WordWise · OpenScrabble · Chess · Hisstastic
Minimal, focused tools for everyday tasks.