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Document Forensics
PDFs are trivial to edit. The edits are invisible. Forensic analysis is how you tell the difference.
Contracts, certificates, financial records, identity documents - they all travel as PDFs, and they're all editable with tools anyone can access. The changes don't show up on screen. TamperCheck looks inside the file - text layers, font tables, metadata, compression patterns - to find what visual inspection can't.
- No document storage
- Digital, scanned or photographed
- ~1 minute per verdict
Last updated:
The problem
Why you can't trust a PDF
PDF was designed to be a portable, fixed-layout format - but it was never designed to be tamper-proof. Anyone with Adobe Acrobat, LibreOffice, or a free online PDF editor can change text, replace images, and alter metadata without leaving visible traces to the naked eye.
Digital signatures help when they're present, but the majority of PDFs in business workflows - bank statements, payslips, invoices, certificates - are not digitally signed. The recipient has no way to verify authenticity without forensic analysis.
The rise of generative AI has made the problem worse. Tools can now produce entire PDFs from text prompts - complete with institutional branding, correct formatting, and plausible content. These documents have never existed in paper form and have no chain of custody to verify.
What we detect
Forensic signals that expose fraud
Text layer integrity
What copy-paste sees vs what the screen shows. Edits that modify text objects without re-rendering the page leave detectable mismatches between the two layers.
Font catalogue consistency
Every PDF references specific fonts. Edit a field with a different tool and the catalogue changes - mixed sources, missing glyphs, metric drift.
Object stream analysis
PDFs are object streams. Add, remove, or modify an object and the structure shows it: orphaned references, incremental save markers, broken cross-reference tables.
Compression artifact analysis
Different tools compress differently. A scan re-saved through an editor shows compression boundary artifacts at the edit edge.
Metadata and producer fingerprint
Creator, producer, dates, tool version - the metadata tells a story. Institutional documents have consistent metadata. Edited files name tools the institution never used.
AI-generated content detection
Fully synthetic PDFs carry noise patterns, rendering quirks, and structural signatures that documents from real institutions or scanners don't.
The solution
Upload any PDF. Get a forensic verdict. No expertise required.
Upload any PDF - bank statement, certificate, contract, invoice - get a forensic verdict back. No forensics expertise needed on your side.
How it works
- Works on any PDF - financial, legal, identity, academic, commercial
- Three analysis layers - structural forensics, computer vision, and AI adjudication
- Findings pinpointed to document regions - each issue tied to a specific element
- Handles scans too - phone photos and flatbed scans of paper documents are first-class inputs
- Single API endpoint - upload, get verdict JSON, done
- per-document pricing with your first top-up matched free
Why us
What you won't get elsewhere
Findings, not a score
We name the field that changed and where it sits on the page.
Others hand you a number to justify.
One endpoint, every type
100+ document types, 190+ countries, no per-type setup.
Elsewhere, each new form is a project.
Catches what was never real
A dedicated pass for AI-generated and deepfake documents.
Template matching only catches edits.
Nothing is retained
Analysed in memory, then discarded. Never trained on.
Most services keep documents for QA.
Live in minutes
Published pricing, no minimum. Test it before you talk to us.
Platforms want a contract first.
Sits alongside your stack
Keep Onfido or Jumio for face match. We add the forensics.
Not a rip-and-replace.
FAQ
Common questions
Can TamperCheck verify password-protected PDFs?
If you can supply the password, yes. Encrypted PDFs that can't be opened are a dead end - but that's true of any verification tool.
Does TamperCheck check digital signatures?
A valid digital signature is already a strong authenticity signal. TamperCheck adds value where it matters most: the majority of business PDFs - statements, payslips, invoices, certificates - that were never signed. That's where forensic analysis is the only check you have.
How is this different from a virus scanner?
Different problem entirely. A virus scanner looks for malicious code. TamperCheck checks whether the document itself has been tampered with, fabricated, or generated by AI.
Can I verify PDFs in bulk?
The API handles concurrent requests. Teams typically run batch verification on document backlogs alongside real-time checks on new uploads.
Or skip the call entirely
We'll match your first top-up in credits, so you can run your own documents through it now.