CRYPTOGRAPHIC SEAL VERIFICATION

Is this document authentic?

Drop any sealed PDF below. We'll cryptographically verify its authenticity, signer credentials, and seal integrity — in seconds. No account. No upload to the cloud.

SKIP THE BROWSER

Verify without leaving your tools.

Install once. Check any PDF, anywhere — right-click to verify.

Free

Chrome extension

Right-click any PDF link on the web. Instant verification without downloading.

Add to Chrome
Coming soon

Acrobat plugin

Verify sealed PDFs inside Adobe Acrobat Reader. Works offline for signed documents.

Install for Acrobat
Step 1 of 3: You drop a PDF
HOW IT WORKS

01 / 03

You drop
a PDF.

The document never leaves your device. Your browser runs the SHA-256 hash locally — the file bytes themselves are never sent anywhere.

SHA-256 · WebCrypto API · client-side only

02 / 03

We read
the seal.

Every sealed PDF carries invisible XMP metadata: a verification code, the signer's credential ID, and the document's original hash — placed there at sealing time.

XMP metadata · PDF/A standard · tamper-evident

03 / 03

Cryptographic
match.

We look up the seal record and compare the hash in the PDF against the hash we stored at sealing time. If they match — byte for byte — the document is authentic.

constant-time compare · no false positives · immutable record