Advanced search for Digital signatures

GroupDocs.Signature provides DigitalSearchOptions class 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 our GitHub examples:

Free Online App

Along with full-featured .NET library we provide simple, but powerful free Apps.

You are welcome to eSign PDF, Word, Excel, PowerPoint documents with free to use online GroupDocs Signature App.