What Can You Verify in a Signed PDF?

A name typed into a PDF and a certificate-based digital signature can both be used to sign electronically. They give the recipient different ways to verify what happened.

An electronic signature might be a typed name, a signature drawn on a screen or a scanned image of a handwritten signature. It can show intent to approve. By itself, though, the visible signature cannot tell you who placed it there—or whether the document changed afterward.

A digital signature uses a certificate to connect a signer to a specific version of a file. Compatible software can check the signature and identify changes to the signed content.

You may hear several terms around this technology. They are variations on a theme, each describing a different piece of the trust process:

• Digital credential: Information issued to a person to support a claim about their identity or status—for example, that they hold a professional designation.

• Digital certificate: A technical certificate that connects an identity to the cryptographic key used for signing.

• Digital signature: The result of using that key to sign a document, allowing a recipient to check signer information and the file’s integrity.

• Digital seal: A term whose meaning depends on context. It may refer to a professional seal displayed on a document or a technical means of authenticating it. An image of a seal alone does not provide the checks of a digital signature.

What gives a signature credibility?

The technology can help show whether a signed file has changed. Trust in the signer also depends on how their identity was verified before a credential was issued and how access to it is controlled. These checks can provide different levels of assurance, from basic to more rigorous verification.

When receiving a signed document, open the original PDF file in software that supports signature validation. Check the signer’s name, the certificate issuer, the validation result and any changes reported after signing. If professional status matters, verify that claim through an appropriate source as well.

The next time a signed PDF lands in your inbox, look beyond the visible signature. Open the signature panel and see what you can verify.