One forged signature can sink your business. Catch document fraud in under 2 seconds.
PDF Verified is automated signature verification software and a digital stamp authentication tool. Cryptographically confirm every signature, company seal and rubber stamp on any PDF — instantly, at scale, with court-ready proof. Stop trusting the eye. Start trusting the math.
Manual verification is a liability
Verifying documents by eye cannot catch a tampered byte. PDF Verified replaces opinion with proof: every signed document carries a SHA-256 fingerprint — change one byte and verification fails instantly.
What PDF Verified does
- Instant tamper detection. Recomputes the document SHA-256 fingerprint and compares it to the sealed original. Any change since signing fails in under 2 seconds.
- Stamp & rubber-stamp authentication. Verify company seals, notary seals and serialized approval stamps against a tamper-locked record, each with live revocation status.
- Multi-page page-swap detection. A QR verification mark sits on every page, so an inserted, swapped or removed page in a long PDF never goes unnoticed.
- Copy-paste forgery exposure. A pasted signature image carries no cryptographic binding and no audit trail, so it is flagged — the #1 way fake signatures slip onto contracts.
- PDF structural forensics. Flags signs of signature tampering: incremental saves after signing, changed trailer /ID, post-signature edits and active content.
- Public, no-account verification. Anyone — counterparty, auditor or court — verifies a digital signature in a PDF by QR, code or upload.
- Bulk document verification API. Verify thousands of documents by hash in one workflow. REST + webhooks for AP, KYC and onboarding pipelines.
- Court-ready audit certificate. Every verification yields signer identities, timestamps, IPs and the cryptographic proof chain.
Built for high-stakes documents
- Legal teams — verify contracts, NDAs and notarized documents are authentic and unaltered before they are enforceable.
- Financial institutions — stop authorization fraud at intake and authenticate signed packets in bulk across KYC/onboarding.
- Logistics — authenticate signed bills of lading, delivery proofs and customs paperwork across multi-page batches.
PDF Verified vs manual checking vs legacy tools
| Capability | PDF Verified | Manual checking | Legacy tools |
|---|---|---|---|
| Speed per document | Under 2 seconds | 2–10 minutes | 30–60 seconds |
| Tamper detection | Cryptographic (SHA-256) | Human eye | Visual / metadata |
| Catches a single altered byte | Yes | No | Rarely |
| Stamp / seal authentication | Yes + revocation | No | No |
| Bulk verification API | Yes | No | Add-on |
| Court-ready audit certificate | Yes | No | Sometimes |
System capability summary
- Integrity: SHA-256 document fingerprinting — tamper detection is mathematically certain.
- Verification surface: public REST verification with per-document and per-stamp tokens, plus QR verification on every page.
- Stamp authentication: serialized, tamper-locked stamp records with auto-incrementing serials and real-time revocation.
- Forensic layer: PDF structural analysis (incremental updates, trailer /ID changes, post-signature edits, active content).
- Bulk verification API: REST endpoints + webhooks for enterprise document pipelines.
- Legal frameworks: ESIGN, UETA and eIDAS, plus equivalents in 190+ countries.
- Audit output: signer hash chain, UTC timestamps, IP capture and a downloadable audit certificate.
Frequently asked questions
How do you detect fake signatures on contracts?
PDF Verified seals every signed document with a SHA-256 cryptographic fingerprint and a tamper-evident audit trail. To verify, it recomputes the document hash and compares it to the sealed original — if a single byte changed, verification fails. A pasted or edited signature carries no cryptographic binding and no audit trail, so it is flagged immediately. Detection takes under 2 seconds, with no account required.
Can a digital signature or notary stamp be forged?
You can copy and paste a signature image, but you cannot forge a PDF Verified signature. The proof is not the picture — it is the SHA-256 hash, the timestamped signer chain and the public verification token. Every notary or company seal resolves to a unique token showing its serial number, the document it was applied to and whether it has been revoked, so a copied rubber stamp fails the check.
How does the bulk document verification API work?
Send document hashes or files to the REST API and PDF Verified matches each against its sealed records, returning authentic/altered status, signer details and the audit trail per document. Webhooks push results into your AP, KYC or onboarding workflow, so thousands of documents are verified automatically.
How do I verify a notary seal or company stamp online?
Scan the stamp QR code or open its verification link. PDF Verified shows the stamp name, serial number, the document it was applied to, and whether it is still valid or has been revoked — so anyone can confirm a notary seal or company stamp is authentic and current, with no account.