How to Validate Digital Signature in PDF in Mobile: A Complete Guide

A signature that is only visible as an image on a PDF is not necessarily a certificate-based digital signature. Therefore, in mobile digital signature verification would be done by checking the signature information and not only by checking the signature graphic.

Is It Possible to Validate Digital Signature in Mobile?

Yes, you can validate digital signatures in mobile in many cases, but the exact process depends on the mobile device, PDF application, certificate and type of digital signature.

Many mobile PDF apps offer features for viewing or validating electronic signatures. Some may have limited support for certificate-based signatures.

If you need to verify an important business, legal or government document, use a PDF application that supports digital signature validation.

The availability of signature verification features may also vary between Android and iOS apps and between different versions of the same app.

How to Validate Digital Signature in PDF in Mobile

Follow below general steps to know how to validate digital signature in PDF in mobile.

Step 1: Open the Signed PDF

First, download or find the digitally signed PDF on your mobile device.

Open with a trusted PDF reader that supports electronic signatures.

If you want to see all the details of a certificate or signature, don't just rely on your phone's basic document preview.

Step 2: Find the Digital Signature

Open the signature page.

Depending on how the document was signed, a certificate-based digital signature may appear as a visible signature field, signature panel, or other signature indication.

If the app has an interactive option, tap the signature or the signature info.

Step 3: View Signature Details

If the PDF application allows you to check the digital signature, look for Signature Details, Validate Signature, Certificate Details or a similar option.

The exact name and location of this feature may differ depending on the application.

Step 4: Verify Signature Status

The application can display if the signature is valid, invalid, unknown or requires additional trust verification.

Just because there is a signature graphic on a page does not mean the signature is valid.

Look at the validation information coming from the application.

Step 5: Verify the Certificate

If there is certificate information, review the details.

Depending on the application, you may be able to view information about the certificate holder, issuer, validity period and other certificate details.

Expired, revoked or not trusted certificates may affect the overall validation result.

Step 6: Find Changes in Documents

One of the main reasons to use certificate-based signatures on PDFs is to help detect changes made after signing.

The software may indicate whether the document has been changed since it was signed.

If the document has been changed in a way that affects the content that has been signed, the signature may no longer be valid.

How to Verify Digital Signature in PDF in Mobile

The method for validating digital signature in PDF on mobile is mostly the same as the verification process.

Open the signed PDF in a compatible application and view the signature information. Verify the application's validation status and certificate details.

Depending on the PDF and the software, you might be able to check:

About the signer

Certificate data

Signature validity

Issuer of Certificate

Certificate lifetime

Change status of document

Trust or validation warnings

The information available depends on the signing technology and the PDF application used.

How to Verify Digital Signature in Mobile

If you are thinking about how to verify digital signature in mobile then opening the PDF is not enough. You will need a PDF reader or a verification application that supports the applicable digital-signature technology.

Open the document, go to the field with the signature and open its properties. If the application supports validation features, check the signature status and certificate information.

Without signature information, the application may not support the needed certificate-based verification.

If so, try a compatible PDF application or open the document in a desktop environment that supports the signature technology you need.

How to Verify Digital Signature Online in Mobile

Some users search to verify digital signatures online on mobile because they want to check a PDF without installing an application.

Some services may provide online verification, but digital signature solutions can also support organizations that regularly work with digitally signed documents. Before uploading a PDF with sensitive information, review the service's privacy policy, security practices and how it handles documents.

If you're dealing with sensitive contracts, financial records, government documents or personal information, you might want to opt for a trusted application or an organizational verification system instead of uploading the document to some unknown online service.

The verification result is only meaningful if the online service also supports the particular signature and certificate technology used in the PDF.

Digital Signature Verification in Mobile: Common Mistakes to Avoid

Do not judge the mobile electronic signatures verification process by its appearance. The signature image can be reproduced or embedded in a document without the need to provide cryptographic verifications based on certificates.

Note: Do not edit or re-save a certificate-signed PDF until you finish verification. Changes in the document may affect the signature.

Another common mistake is to use an unknown online verification service for sensitive documents. Think about the confidentiality of the information before uploading a PDF.

Finally, please make sure you are looking at the correct version of the document. If there are multiple versions, verify the specific PDF that was received or submitted.

Best Practices for Digital Signature Validation in Mobile

Some practices while validating digital signature in mobile are:

Use a PDF program that allows electronic signatures and is reliable.

Check the real signature status, not only the appearance of the signature.

If available, review certificate details.

Make sure the certificate is valid and trusted.

Make sure the document has been altered after it is signed.

Always verify a PDF before you sign it electronically.

Never upload sensitive documents to online verification services you don't trust.

Download the full PDF before trying validation.

Mobile support is limited. Check the details with the desktop software.

Please save a copy of the original document for your records.

Last check you are viewing the correct version of the document. If there are multiple versions check the specific PDF that was sent/received. For organizations that process a large number of signed documents, digital signing solutions can help to create a more structured signing process.

Final Thoughts

Checking a digital signature on a mobile device is a useful way to confirm the authenticity and integrity of a digitally signed PDF. With a compatible PDF app you can view the certificate and signature information right on your phone. Always verify the signature status and check that the document was not altered after signing.

Do not use unknown online verification services for documents you consider confidential. If your mobile app doesn't have verification features, you can use trusted desktop software for a more thorough check.

If you work with signed PDFs frequently, a good digital signature solution can make the process of checking them much easier and more organized. When verifying, always use trusted software and keep your documents safe.