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Authentic PDF Digital Signatures provide tamper-proof documents

Instant verification your documents are untampered, authentic, and regulator-ready.

Proof your documents are unchanged

Certify your PDFs haven’t changed since you sealed them - without leaving Acrobat

Proof your documents came from you

Certify that your documents came from your company with a custom certificate (Pro subscription)

Streamlined audits

Easily demonstrate exactly what you documented and when.

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Our certificates are recognized by Adobe Acrobat and eIDAS. Acrobat valid signature

How PDF Digital Signatures Prove Authenticity

When a PDF is sealed with a digital signature, it gets a unique fingerprint. From that moment on, any change — even a single word — will break the seal and be detected.

Adobe Acrobat verifies this automatically and shows the green checkmark when the document is authentic and unchanged. This gives your agreements, reports, and records legal standing and protects your organization against tampering and fraud.

How PDF Sealing Works

(Click any step to learn more)

Step 1: Create a unique fingerprint

Step 1: Create a unique fingerprint

Your PDF gets a unique digital fingerprint. If even one word changes, the fingerprint changes.

Step 2: Lock with your certified seal

Step 2: Lock with your certified seal

We lock that fingerprint with a certified seal tied to your business identity and embed the seal into your document. Any change breaks the seal.

Step 3: Distribute

Step 3: Distribute

Your document can now safely be distributed without worry that it will be tampered.

Later, when anyone opens your document:

Step 1: Acrobat verifies the embedded seal

Step 1: Acrobat verifies the embedded seal

Acrobat confirms that the seal comes from your business.

Step 2: It compares the sealed fingerprint to the document data

Step 2: It compares the sealed fingerprint to the document data

Only an authentic PDF will have a fingerprint that matches the one in its seal.

Step 3: If the it’s a match, the document is authentic

Step 3: If the it’s a match, the document is authentic

The PDF is unmodified since it was sealed
It came from the indicated signer
Nothing has changed since it was sealed
Acrobat displays this at the top of the PDF:

Valid Signature

If the fingerprints don’t match, it’s been modified

If the fingerprints don’t match, it’s been modified

The PDF is tampered
The document cannot be trusted
Acrobat displays this at the top of the PDF:

Invalid Signature

Benefits of Authentic Digital Signatures

Trust: No one can alter invoices or contracts without detection.
Pass audits: Regulators see Adobe’s green check instantly.
Protect your reputation: Clients know your documents are authentic.

With Trusted Signatures, you seal documents in seconds — no subscriptions, no complexity.

Learn more about our secure PDF signing process and easy-to-use tools.

See it in action

See how our services provide the assurance you need

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Want peace of mind?

Trusted Signatures provides the fastest, most affordable, secure PDF signatures on the internet.

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