How to Validate Digital Signatures - CargoSmart Help A digital signature is the most secure and reliable way of protecting and authenticating e-documents sent electronically over the Internet. A valid digital signature can verify the identity of the sender and also validate that no tampering has taken place at any time since its creation. You must have Adobe Acrobat 6.0 or higher in order to validate the electronic signature. To validate the digital signature on your invoice documents: With the invoice document open in Adobe Acrobat, open the Signatures tab to the left of the screen Right click on the desired signature and choose "Validate Signature" from the options menu You will be presented with a dialog box that states whether or not the digital signature is valid, and if the invoice document has been modified or not. You may also configure your Adobe Acrobat reader (version 6.0) to automatically validate digital signatures when the document is opened: Start Adobe Reader In the menu, click on Edit, Preferences Click on the Digital Signatures selection Check the "Verify signature when the document is opened" checkbox Choose the "Always use the default method (overrides the document-specified)" radio button Click on the Advanced Preferences button On the Advanced Preferences dialog box, check on the "Enable importing of identities from the Windows Certificate Store into the Acrobat Trusted Identities list" and "Validating Signatures" checkboxes Click on OK Click on OK on the Preferences dialog box Now, when you open a signed PDF file and click on the Signatures tab on the left to the screen, if the digital signature is valid, you will see a green check to the left of the signature line.