What is Tamper-Evident Seal?

A cryptographic seal that makes any change to a document detectable after it is signed.

A tamper-evident seal binds a document to a cryptographic fingerprint (SHA-256) at the moment of signing. Because the hash changes completely if even one byte is altered, anyone can re-compute it and compare against the published value to prove the document is unmodified. Unlike a physical wax or rubber seal, a digital tamper-evident seal is verifiable remotely, by anyone, with no special tools — and PDF Verified pairs it with a public QR verification page and an append-only audit trail.

How a tamper-evident seal works

At signing, PDF Verified hashes the exact document bytes with SHA-256 and records the value on a public verification page, with a visible seal mark on the PDF. To verify, re-hash the file: a match proves integrity; a mismatch proves tampering.

Seal vs signature vs stamp

The signature captures intent, the stamp conveys authority, and the tamper-evident seal proves the file has not changed since. Together they make a document both authoritative and verifiable.