PDF Integrity Check
HTPBE.tech performs a multi-layer PDF integrity check that examines internal metadata, file structure, and digital signatures to determine whether a PDF document has been altered after creation.
Detect hidden modifications in invoices, contracts, certificates, and financial documents.
What a PDF Integrity Check Examines
Every PDF carries hidden evidence of its history. Here is what to look for.
Metadata consistency — creation and modification timestamps
The integrity check compares the PDF’s internal creation date against its modification date. A document that should be unmodified will have matching or very close timestamps. A significant gap between them is direct evidence of post-creation editing.
Application fingerprints — creator and producer fields
Every PDF stores which software created it and which software last processed it. An integrity failure is indicated when the producer application is a known editing tool that would not appear in a legitimate document workflow.
Cross-reference table count — structural revision history
A freshly created PDF has a single cross-reference table. Each subsequent edit appends another. Multiple cross-reference sections in the file are a direct structural indicator of post-creation modification.
Digital signature validity and completeness
If a PDF was digitally signed, integrity requires that signature to remain valid. A post-signature modification breaks the cryptographic hash. A missing signature on a document that carried one is equally suspicious.
The Easy Way: Use HTPBE
All checks run automatically in seconds — no technical knowledge required.
Upload the PDF you want to check
Drop any PDF file up to 10 MB on the checker. No account required.
Integrity analysis runs across all layers
All checks — metadata, file structure, revision history, and signatures — run simultaneously in under 5 seconds.
Get the integrity result
A clear pass or fail verdict with the specific findings that determined the result, explained in plain language.
Frequently Asked Questions
What does a PDF integrity check actually check?
It checks four layers: metadata (creation date, modification date, creator and producer applications), file structure (cross-reference table count and revision layers), digital signatures (presence, validity, and any post-signature changes), and embedded content (JavaScript, hidden file attachments). All four layers are analyzed simultaneously.
How is a PDF integrity check different from just reading a PDF?
Reading a PDF shows you the visible content. An integrity check examines the internal file structure and metadata — evidence that is completely invisible in any PDF viewer. Editing tools can change numbers and text while leaving the visual layout unchanged; only structural analysis reveals the modification.
Can I run PDF integrity checks in bulk using an API?
Yes. The HTPBE API supports automated integrity checks at scale. It is used by fintech companies, HR platforms, and compliance teams to check documents as part of their intake workflows. API access starts at $15/month with test keys available on all plans.
Does the integrity check work on password-protected PDFs?
No. Password-protected and encrypted PDFs cannot be analyzed — the encryption blocks access to the internal structure the tool needs to examine. Remove the password before uploading.