确定pdf文件是否在c＃中具有数字签名而不验证签名

Question

有没有办法检查PDF文件是否有数字签名？

Answer 1

Free Spire.PDF库提供了一种功能，可以检查PDF文件是否具有数字签名而无需进行验证。您可以从NuGet Package Manager获取Free Spire.PDF dll并参考以下代码。

//Load PDF file
PdfDocument pdf = new PdfDocument();
pdf.LoadFromFile("Input.pdf");

//Gets the loaded form in the PDF file
PdfFormWidget form = pdf.Form as PdfFormWidget;

//Determine if there is any signature field among the form fields and whether it contains digital signature
for (int i = 0; i < form.FieldsWidget.Count; i++)
{
    var field = form.FieldsWidget[i] as PdfSignatureFieldWidget;
    if (field != null && field.Signature != null)
    {
        Console.WriteLine("This form field has digital signature!");
    }
}

注意：我是Spire的员工。