Advanced search for Digital signatures

GroupDocs.SignatureΒ providesΒ DigitalSearchOptionsΒ classΒ to specify different options to search for Digital Signatures.

Here are the steps to search for digital signatures within the document with GroupDocs.Signature:

This example shows how to make advanced search for Digital signature in the document.

using (Signature signature = new Signature("signed.pdf"))
{
    DigitalSearchOptions options = new DigitalSearchOptions()
    {
        // specify special search criteria
        Comments = "Test comment",
        // certificate issues criteria
        IssuerName = "John",
        // digital certificate subject
        SubjectName = "Test",
        // specify date range period of signature
        SignDateTimeFrom = DateTime.Now.AddMonths(-1),
        SignDateTimeTo = DateTime.Now,
        //
    };
    // search for signatures in document
    List<DigitalSignature> signatures = signature.Search<DigitalSignature>(options);
    Console.WriteLine("\nSource document contains following signatures.");
    foreach (var digitalSignature in signatures)
    {
        Console.WriteLine("Digital signature found from {0} with validation flag {1}. Certificate SN {2}",
            digitalSignature.SignTime, digitalSignature.IsValid, digitalSignature.Certificate?.SerialNumber);
    }
}

More resources

GitHub Examples

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

Free Online Apps

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.