Frequently Asked Questions

HashNotary is a blockchain-based document certification service. We create an immutable, timestamped cryptographic fingerprint (SHA-256 hash) of your document on the Polygon blockchain, providing mathematically verifiable proof that your document existed at a specific point in time.

Traditional notaries verify identity and witness signatures — they require physical presence, cost $50-300 per document, and are limited by geography and office hours. HashNotary certifies document existence and integrity — it works instantly, 24/7, from anywhere in the world, for $15 per document. Note: HashNotary is not a substitute for legal notarization where required by law.

Yes — because we never see it. HashNotary uses Zero-Knowledge Architecture: your browser generates the cryptographic hash locally on your device. Your original file never leaves your computer, never travels over the internet, and never touches our servers.

We use Polygon (an Ethereum Layer 2 network). It provides the security guarantees of Ethereum with transaction costs under $0.01 and confirmation times of 2-3 seconds.

Your blockchain seals are permanent. They exist on the Polygon blockchain, which is a decentralized public ledger maintained by thousands of nodes worldwide. Even if HashNotary ceased operations, your seals would remain verifiable forever through any Polygon blockchain explorer.

All payments are processed in cryptocurrency on the Polygon network. We accept MATIC and USDC tokens. You'll need a Web3 wallet like MetaMask to make payments. We do not accept credit cards, bank transfers, or PayPal.

No! Your first 3 seals are completely free — no wallet or payment needed. After that, you'll need a MetaMask wallet with MATIC or USDC on the Polygon network.

Yes. PDFs, images, videos, spreadsheets, source code, 3D models, audio files — if it's a file, we can seal it. There are no format restrictions.

Every sealed document receives a unique QR code and verification URL. Anyone can scan the QR code or visit the URL to instantly verify the document's authenticity — no account needed.

It means we have zero knowledge of your document's contents. We only see and store the mathematical hash — a 64-character code that uniquely identifies your document but cannot be used to reconstruct it. Think of it as a digital fingerprint: it can identify the document, but you can't rebuild a person from a fingerprint.

No. Hashing is a one-way function — you can generate a hash from a file, but you cannot generate a file from a hash. This is fundamentally different from encryption, where data can be decrypted with the right key. SHA-256 hashes are irreversible by design.

Pay-as-you-go: $15 per document. Professional: $99/month for 20 documents. Enterprise: $499/month for unlimited documents with API access. Your first 3 seals are free.

Blockchain timestamps are increasingly accepted as evidence in courts worldwide. However, legal acceptance varies by jurisdiction. HashNotary provides cryptographic proof of existence — consult a legal professional regarding admissibility in your specific jurisdiction.

Absolutely. Our Professional plan includes white-label certificates with your branding. Enterprise plans include REST API access for automated workflows, batch processing, and webhook integrations.