PQCServer Notary · ML-DSA FIPS-204 · Quantum-Safe

Prove your document
existed, unchanged,
at this exact moment

Sign any document with a post-quantum ML-DSA signature. The server adds a cryptographic timestamp. Anyone can verify the receipt — forever. Your document never leaves your browser.

✍️ Sign a document ✔️ Verify a receipt
NIST FIPS-204 · ML-DSA-65 SIGNATURE · SHA-256 + SHA-512 HASH · ZERO-KNOWLEDGE · DOCUMENT NEVER LEAVES BROWSER · PUBLICLY VERIFIABLE · QUANTUM-RESISTANT · PERMANENT RECEIPT · FREE · NIST FIPS-204 · ML-DSA-65 SIGNATURE · SHA-256 + SHA-512 HASH · ZERO-KNOWLEDGE · DOCUMENT NEVER LEAVES BROWSER · PUBLICLY VERIFIABLE ·
How it works
Four steps. Permanent proof.

Your document is hashed locally — the server only receives the fingerprint.

01
Hash locally

Your browser computes SHA-256 and SHA-512 fingerprints of the document. The file itself stays on your device — zero bytes uploaded.

02
Sign with ML-DSA

You sign the hash with your ML-DSA private key (NIST FIPS-204). The signature mathematically proves you authorized this exact document.

03
Server timestamps

PQCServer adds a certified timestamp and countersignature. This anchors the document to a precise moment in time.

04
Notary Receipt

You receive a JSON receipt with a permanent verify URL. Anyone can check it anytime — no account needed to verify.

The Receipt
What you get

A self-contained cryptographic proof. Download it as JSON or share the verify URL.

// NOTARY RECEIPT — pqcserver.com
"receipt_id": "NTR-x7k2p9abcd",
"verify_url": "https://pqcserver.com/verify/NTR-x7k2p9abcd",

// DOCUMENT FINGERPRINT (never the file itself)
"document": {
  "hash_sha256": "a3f9c2e1...",
  "hash_sha512": "7bc2d4f8...",
  "filename": "contratto_2026.pdf",
  "size_bytes": 245120
},

// YOUR ML-DSA SIGNATURE
"signature": {
  "algorithm": "ML-DSA-65",
  "value": "MEQCIA...",
  "signed_at": "2026-03-17T11:30:00Z"
},

// SERVER TIMESTAMP + COUNTERSIGNATURE
"timestamp": {
  "server": "pqcserver.com",
  "issued_at": "2026-03-17T11:30:02Z",
  "server_signature": "ABCDEF...",
  "server_public_key":"base64..."
}
Use cases
Who uses it
⚖️
Contracts & Agreements

Prove a contract existed in its current form before signing with a traditional notary. Establish precedence in case of disputes about document contents or dates.

💡
Intellectual Property

Timestamp creative works, inventions, research papers, or source code. Establish prior art without expensive patent filings during early development.

🏥
Medical & Clinical Records

Prove a medical report was issued on a specific date. Verify a clinical protocol has not been modified retroactively. Critical for compliance and liability.

📰
Journalism & Evidence

Journalists can timestamp sensitive documents and evidence. Prove source documents were unaltered before publication. Protect whistleblower materials.

🏗️
Construction & Real Estate

Timestamp project drawings, permits, inspections, and site reports. Essential when disputes arise years after a project about the state of documentation at a given date.

💻
Software & Code Signing

Sign software releases, configuration files, and security policies. Verify that code deployed in production matches the signed version. Detect tampering.

Legal recognition
Growing legal standing

ML-DSA is a NIST federal standard (FIPS-204, Aug 2024). Legal recognition of PQC signatures is actively evolving — the EU, US, and other jurisdictions are integrating it into their frameworks.

Important: PQCServer Notary receipts provide strong cryptographic proof but are not a substitute for notarized signatures in jurisdictions requiring them for specific document types (real estate, wills, powers of attorney). Consult a legal professional for your specific use case. The technical validity of ML-DSA signatures is absolute — legal recognition depends on jurisdiction.
Ready to sign your first document?

Free. No size limit. Document never leaves your browser. Permanent receipt. Publicly verifiable forever.

✍️ Sign a document ✔️ Verify a receipt 🔑 Get your keys first