Delete Digital signatures from documents Leave feedback

GroupDocs.Signature provides DigitalSignature class to manipulate digital electronic signatures and delete them from the documents. Please be aware that Delete method modifies the same document that was passed to constructor of the Signature class.

Important information. Please be aware that digitally signed documents with valid certificates (pfx files) are secured and verified. Changing digitally signed document makes them untrusted from the digital verification perspective. At this moment only Pdf documents support deletion of the specific digital signatures in case of many ones were added. Most documents support deletion of all digital signatures at once without separate certificates removal. It’s strongly recommened to use deletion of electronic digital signatures by signature type Digital. See example [Delete Signatures of the certain type]

Here are the steps to delete Digital signature from the document with GroupDocs.Signature:

• Create new instance of Signature class and pass source document path or its stream as a constructor parameter;
• Instantiate DigitalSearchOptions object with desired properties;
• Call Search method to obtain list of DigitalSignatures;
• Select from list DigitalSignature object(s) that should be removed from the document;
• Call Signature object Delete method and pass one or several signatures to it.

This example shows how to delete Digital signature that was found using Search method.

using (Signature signature = new Signature("signed.pdf"))
{
    // Search for electronic Digital signatures in the document
    List<DigitalSignature> signatures = 
        signature.Search<DigitalSignature>(SignatureType.Digital);

    if (signatures.Count > 0)
    {
        DigitalSignature digitalSignature = signatures[0];
        bool result = signature.Delete(digitalSignature);

        if (result)
        {
            Console.WriteLine(
                $"Digital signature #{digitalSignature.Thumbprint} from " +
                $"{digitalSignature.SignTime.ToShortDateString()} was deleted."
            );
        }
        else
        {
            Console.WriteLine(
                $"Signature was not deleted from the document! " +
                $"Signature# {digitalSignature.Thumbprint} was not found!"
            );
        }
    }
}

To learn more about document eSign features, please refer to the Advanced usage section.

You may easily run the code above and see the feature in action in our GitHub examples:

• GroupDocs.Signature for .NET examples, plugins, and showcase
• GroupDocs.Signature for Java examples, plugins, and showcase
• Document Signature for .NET MVC UI Example
• Document Signature for .NET App WebForms UI Example
• Document Signature for Java App Dropwizard UI Example
• Document Signature for Java Spring UI Example

Along with the full-featured .NET library, we provide simple but powerful free online apps.

To sign PDF, Word, Excel, PowerPoint, and other documents you can use the online apps from the GroupDocs.Signature App Product Family.